mmm... no entiendo muy bien la pregunta, pero creo que es, que pase la plantilla normal (default) a una que importé
pon el codigo de la plantilla que importaste
El template original es PeaceBlue, lo que pasa esque modifiqué toda la plantilla, pero nada importante. Aquí el code de PeaceBlue:

Código:
<?xml version="1.0" encoding="UTF-8"?>
<theme name="PeaceBlue" version="1413">
    <properties>
        <templateset><![CDATA[3]]></templateset>
        <editortheme><![CDATA[default]]></editortheme>
        <imgdir><![CDATA[images/peaceblue]]></imgdir>
        <logo><![CDATA[images/peaceblue/logo.png]]></logo>
        <tablespace><![CDATA[4]]></tablespace>
        <borderwidth><![CDATA[1]]></borderwidth>
    </properties>
    <stylesheets>
        <stylesheet name="global.css" version="1413"><![CDATA[body {
    background: #353535 url(images/peaceblue/bg.gif);
    color: #000;
    text-align: center;
    line-height: 1.4;
    padding: 0px;
    margin: 0px;
    font-family: Verdana, Arial, Sans-Serif;
    font-size: 13px;
}

a:link {
    color: #141414;
    text-decoration: none;
}

a:visited {
    color: #141414;
    text-decoration: none;
}

a:hover, a:active {
    color: #141414;
    text-decoration: underline;
}

#container {
    background: #efefef;
    width: 900px;
    color: #000000;
    border-right: 2px solid #000;
    border-left: 2px solid #000;
    margin: auto auto;
    text-align: left;
}

#content {
    background: #efefef;
    width: auto !important;
    padding-right: 20px;
    padding-left: 30px;
}

#header {
    background: #000 url(images/peaceblue/head-bg.png);
}

.logo {
    clear: both;
    padding: 20px;
    float: left;
}

.menu {
    background: #000 url(images/peaceblue/link-nav.png);
    height: 46px;
    clear: both;
}

.menu ul {
    color: #fff;
    text-align: right;
              padding: 13px;
}

.menu ul a:link {
    color: #fff;
    text-decoration: none;
}

.menu ul a:visited {
    color: #fff;
    text-decoration: none;
}

.menu ul a:hover, .menu ul a:active {
    color: #fff;
    text-decoration: underline;
}

#panel-pad {
             padding-top: 12px;
             padding-right: 10px;
}

#panel {
    background: url(images/peaceblue/user-bg.png) no-repeat;
    width: 300px;
        height: 90px;
    color: #fff;
    float: right;
    font-size: 11px;
}

#panel a:hover {
              color: #fff;
}

#panel a:link {
              color: #fff;
}

#panel a:visited {
              color: #fff;
}

#panel-text {
    width: 290px;
    margin: auto;
    float: right;
    padding-right: 48px;
    padding-top: 14px;
    text-align: right;
}

#bread {
    padding: 10px;
    float: left;
    clear: both;
    
    font-size: 11px;
}

#options {
               width: 250px;
               padding: 10px;
               float: right;  
               color: #000;
}

#options a:link {
    color: #000;
    text-decoration: underline;
}

#options a:hover {
    color: #061545;
    text-decoration: underline;
}

#options a:visited {
    color: #000;
    text-decoration: underline;
}

table {
    font-family: Verdana, Arial, Sans-Serif;
    font-size: 13px;
}

.tborder {
    background: #ddd;
    width: 100%;
    margin: auto auto;
}

.thead {
    background: #1d3170 url(images/peaceblue/cat-bg.png) top left repeat-x;
    color: #ffffff;
    
    padding: 10px;
}

.thead a:link {
    color: #ffffff;
    text-decoration: none;
}

.thead a:visited {
    color: #ffffff;
    text-decoration: none;
}

.thead a:hover, .thead a:active {
    color: #ffffff;
    text-decoration: underline;
}

.tcat {
    background: #000 url(images/peaceblue/t-head.png) repeat-x;;
    color: #fff;
    height: 22px;
    
    font-size: 12px;
}

.tcat a:link {
    color: #fff;
}

.tcat a:visited {
    color: #fff;
}

.tcat a:hover, .tcat a:active {
    color: #fff;
}

.trow1 {
    background: #f5f5f5;
}

.trow2 {
    background: #EFEFEF;
}

.trow_shaded {
    background: #ffdde0;
}

.trow_selected td {
    background: #FFFBD9;
}

.trow_sep {
    background: #e5e5e5;
    color: #000;
    font-size: 12px;
    font-weight: bold;
}

.tfoot {
    background: #000 url(images/peaceblue/t-head.png) top left repeat-x;
    color: #ffffff;
}

.tfoot a:link {
    color: #ffffff;
    text-decoration: none;
}

.tfoot a:visited {
    color: #ffffff;
    text-decoration: none;
}

.tfoot a:hover, .tfoot a:active {
    color: #ffffff;
    text-decoration: underline;
}

.bottommenu {
    background: #efefef;
    color: #000000;
    border: 1px solid #4874a3;
    padding: 10px;
}

.navigation {
    color: #000000;
    font-size: 11px;
}

.navigation a:link {
    font-weight: bold;
}

.navigation a:visited {
    text-decoration: bold;
}

.navigation a:hover, .navigation a:active {
    text-decoration: bold;
}

.navigation .active {
    color: #000000;
    font-size: small;
}

.smalltext {
    font-size: 11px;
              padding: 10px;
}

.largetext {
    font-size: 16px;
    font-weight: bold;
}

input.textbox {
    background: #ffffff;
    color: #000000;
    border: 1px solid #0f5c8e;
    padding: 1px;
}

textarea {
    background: #ffffff;
    color: #000000;
    border: 1px solid #0f5c8e;
    padding: 2px;
    font-family: Verdana, Arial, Sans-Serif;
    line-height: 1.4;
    font-size: 13px;
}

select {
    background: #ffffff;
    border: 1px solid #0f5c8e;
}

.editor {
    background: #f1f1f1;
    border: 1px solid #ccc;
}

.editor_control_bar {
    background: #fff;
    border: 1px solid #0f5c8e;
}

.autocomplete {
    background: #fff;
    border: 1px solid #000;
    color: black;
}

.autocomplete_selected {
    background: #adcee7;
    color: #000;
}

.popup_menu {
    background: #ccc;
    border: 1px solid #000;
}

.popup_menu .popup_item {
    background: #fff;
    color: #000;
}

.popup_menu .popup_item:hover {
    background: #C7DBEE;
    color: #000;
}

.trow_reputation_positive {
    background: #ccffcc;
}

.trow_reputation_negative {
    background: #ffcccc;
}

.reputation_positive {
    color: green;
}

.reputation_neutral {
    color: #444;
}

.reputation_negative {
    color: red;
}

.invalid_field {
    border: 1px solid #f30;
    color: #f30;
}

.valid_field {
    border: 1px solid #0c0;
}

.validation_error {
    background: url(images/invalid.gif) no-repeat center left;
    color: #f30;
    margin: 5px 0;
    padding: 5px;
    font-weight: bold;
    font-size: 11px;
    padding-left: 22px;
}

.validation_success {
    background: url(images/valid.gif) no-repeat center left;
    color: #00b200;
    margin: 5px 0;
    padding: 5px;
    font-weight: bold;
    font-size: 11px;
    padding-left: 22px;
}

.validation_loading {
    background: url(images/spinner.gif) no-repeat center left;
    color: #555;
    margin: 5px 0;
    padding: 5px;
    font-weight: bold;
    font-size: 11px;
    padding-left: 22px;
}

/* Additional CSS (Master) */
img {
    border: none;
}

.clear {
    clear: both;
}

.hidden {
    display: none;
    float: none;
    width: 1%;
}

.float_left {
    float: left;
}

.float_right {
    float: right;
}

.menu ul {
    list-style: none;
    margin: 0;
}

.menu li {
    display: inline;
    padding-left: 5px;
}

.menu img {
    padding-right: 5px;
    vertical-align: top;
}

#panel .links {
    margin: 0;
}

.expcolimage {
    float: right;
    width: auto;
    vertical-align: middle;
}

img.attachment {
    border: 1px solid #E9E5D7;
    padding: 2px;
}

hr {
    background-color: #000000;
    color: #000000;
    height: 1px;
    border: 0px;
}

#copyright {
    color: #fff;
    font: 11px Verdana, Arial, Sans-Serif;
    margin: 0;
}

#copyright a:link {
    color: #fff;
    font: 11px Verdana, Arial, Sans-Serif;
    
    text-decoration: underline;
}

#copyright a:hover {
    color: #fff;
    font: 11px Verdana, Arial, Sans-Serif;
    
    text-decoration: underline;
}

#copyright a:visited {
    color: #fff;
    font: 11px Verdana, Arial, Sans-Serif;
    
    text-decoration: underline;
}

#debug {
    float: right;
    text-align: right;
    margin-top: 0;
}

blockquote {
    border: 1px solid #ccc;
    margin: 0;
    background: #fff;
    padding: 4px;
}

blockquote cite {
    font-weight: bold;
    border-bottom: 1px solid #ccc;
    font-style: normal;
    display: block;
    margin: 4px 0;
}

blockquote cite span {
    float: right;
    font-weight: normal;
}

blockquote cite span.highlight {
    float: none;
    font-weight: bold;
    padding-bottom: 0;
}

.codeblock {
    background: #fff;
    border: 1px solid #ccc;
    padding: 4px;
}

.codeblock .title {
    border-bottom: 1px solid #ccc;
    font-weight: bold;
    margin: 4px 0;
}

.codeblock code {
    overflow: auto;
    height: auto;
    max-height: 200px;
    display: block;
    font-family: Monaco, Consolas, Courier, monospace;
    font-size: 13px;
}

.subforumicon {
    border: 0;
    vertical-align: middle;
}

.separator {
    margin: 5px;
    padding: 0;
    height: 0px;
    font-size: 1px;
    list-style-type: none;
}

form {
    margin: 0;
    padding: 0;
}

.popup_menu .popup_item_container {
    margin: 1px;
    text-align: left;
}

.popup_menu .popup_item {
    display: block;
    padding: 3px;
    text-decoration: none;
    white-space: nowrap;
}

.popup_menu a.popup_item:hover {
    text-decoration: none;
}

.autocomplete {
    text-align: left;
}

.subject_new {
    font-weight: bold;
}

.highlight {
    background: #FFFFCC;
    padding: 3px;
}

.pm_alert {
    background: #FFF6BF;
    border: 1px solid #FFD324;
    text-align: center;
    padding: 5px 20px;
    font-size: 11px;
}

.red_alert {
    background: #FBE3E4;
    border: 1px solid #A5161A;
    color: #A5161A;
    text-align: center;
    padding: 5px 20px;
    font-size: 11px;
}

.high_warning {
    color: #CC0000;
}

.moderate_warning {
    color: #F3611B;
}

.low_warning {
    color: #AE5700;
}

div.error {
    padding: 5px 10px;
    border-top: 2px solid #FFD324;
    border-bottom: 2px solid #FFD324;
    background: #FFF6BF;
    font-size: 12px;
}

div.error p {
    margin: 0;
    color: #000;
    font-weight: normal;
}

div.error p em {
    font-style: normal;
    font-weight: bold;
    padding-left: 24px;
    display: block;
    color: #C00;
    background: url('images/error.gif') no-repeat 0;
}

div.error.ul {
    margin-left: 24px;
}

.online {
    color: #15A018;
}

.offline {
    color: #C7C7C7;
}

.pagination {
    font-size: 11px;
    padding-top: 10px;
    margin-bottom: 5px;
}

.tfoot .pagination, .tcat .pagination {
    padding-top: 0;
}

.pagination .pages {
    font-weight: bold;
}

.pagination .pagination_current, .pagination a {
    padding: 2px 6px;
    margin-bottom: 3px;
}

.pagination a {
    border: 1px solid #81A2C4;
}

.pagination .pagination_current {
    background: #F5F5F5;
    border: 1px solid #81A2C4;
    font-weight: bold;
}

.pagination a:hover {
    background: #F5F5F5;
    text-decoration: none;
}

.thread_legend, .thread_legend dd {
    margin: 0;
    padding: 0;
}

.thread_legend dd {
    padding-bottom: 4px;
    margin-right: 15px;
}

.thread_legend img {
    margin-right: 4px;
    vertical-align: bottom;
}

.forum_legend, .forum_legend dt, .forum_legend dd {
    margin: 0;
    padding: 0;
}

.forum_legend dd {
    float: left;
    margin-right: 10px;
}

.forum_legend dt {
    margin-right: 10px;
    float: left;
}

.success_message {
    color: #00b200;
    font-weight: bold;
    font-size: 10px;
    margin-bottom: 10px;
}

.error_message {
    color: #C00;
    font-weight: bold;
    font-size: 10px;
    margin-bottom: 10px;
}

.post_body {
    padding: 5px;
}

.post_content {
    padding: 5px 10px;
}

.quick_jump {
    background: url('images/jump.gif') no-repeat 0;
    width: 13px;
    height: 13px;
    padding-left: 13px; /* amount of padding needed for image to fully show */
    vertical-align: middle;
    border: none;
}

#lang-bar {
    background: url(images/peaceblue/bread-nav.png);
    height: 40px;
}

#footer-bar {
    background: url(images/peaceblue/footer-bg.png);
    height: 37px;
    border-bottom: #000 2px solid;
    border-top: #000 1px solid;
}

]]>
        </stylesheet>
    </stylesheets>
    <templates>
        <template name="header" version="1413"><![CDATA[<div id="container">
        <a name="top" id="top"></a>
        <div id="header">
            <div class="logo">
                                                          <a href="{$mybb->settings['bburl']}/index.php"><img src="{$theme['logo']}" alt="{$mybb->settings['bbname']}" title="{$mybb->settings['bbname']}" /></a>
                                          </div>
                                          <div id="panel-pad">
            <div id="panel">
                           <div id="panel-text">
                {$welcomeblock}
                           </div>
            </div>
                                          </div>
            <div class="menu">
                <ul>
                                                                       {$modcplink}
                                                                        {$admincplink}
                    <li><a href="{$mybb->settings['bburl']}/search.php"><img src="{$mybb->settings['bburl']}/{$theme['imgdir']}/toplinks/search.gif" alt="" title="" />{$lang->toplinks_search}</a></li>
                    <li><a href="{$mybb->settings['bburl']}/memberlist.php"><img src="{$mybb->settings['bburl']}/{$theme['imgdir']}/toplinks/memberlist.gif" alt="" title="" />{$lang->toplinks_memberlist}</a></li>
                    <li><a href="{$mybb->settings['bburl']}/calendar.php"><img src="{$mybb->settings['bburl']}/{$theme['imgdir']}/toplinks/calendar.gif" alt="" title="" />{$lang->toplinks_calendar}</a></li>
                    <li><a href="{$mybb->settings['bburl']}/misc.php?action=help"><img src="{$mybb->settings['bburl']}/{$theme['imgdir']}/toplinks/help.gif" alt="" title="" />{$lang->toplinks_help}</a></li>
                </ul>
            </div>
                                          <div style="background: url(images/peaceblue/bread-nav.png); height: 40px;">
                                                   <div id="bread">
                                                                  <navigation>
                                                   </div>
                                                   <div id="options">
                                                                   <a href="{$mybb->settings['bburl']}/search.php?action=getnew">{$lang->welcome_newposts}</a> | <a href="{$mybb->settings['bburl']}/search.php?action=getdaily">{$lang->welcome_todaysposts}</a>
                                                    </div>
                                          </div>
            <hr class="hidden" />
        </div>
        <hr class="hidden" />
        <br class="clear" />
        <div id="content">
            {$pm_notice}
            {$bannedwarning}
            {$bbclosedwarning}
            {$unreadreports}
            <br />]]></template>
        <template name="header_welcomeblock_member" version="1413"><![CDATA[<div style="float: right;margin-left:8px"">
<img src="{$mybb->user['avatar']}" style="width: 60px; height: 60px;" />
</div>
<span style="padding-top: 10px;">
        <span style="font-size: 13px;">Welcome, {$mybb->user['username']} <br /> </span>
Posts: {$mybb->user['postnum']}<br />
<a href="{$mybb->settings['bburl']}/usercp.php"><strong>{$lang->welcome_usercp}</strong></a> - <a href="{$mybb->settings['bburl']}/private.php">PM's</a> - <a href="{$mybb->settings['bburl']}/member.php?action=logout&amp;logoutkey={$mybb->user['logoutkey']}">Logout</a>
</span>]]></template>
        <template name="header_welcomeblock_member_admin" version="1413"><![CDATA[<li><a href="{$mybb->settings['bburl']}/{$config['admin_dir']}/index.php"><img src="{$mybb->settings['bburl']}/{$theme['imgdir']}/toplinks/admincp.gif" alt="" title="" />{$lang->welcome_admin}</a></li>]]></template>
        <template name="forumbit_depth1_cat" version="1413"><![CDATA[<table border="0" cellspacing="{$theme['borderwidth']}" cellpadding="{$theme['tablespace']}" class="tborder">
<thead>
<tr>
<td class="thead" colspan="5">
<div class="expcolimage"><img src="{$theme['imgdir']}/{$expcolimage}" id="cat_{$forum['fid']}_img" class="expander" alt="{$expaltext}" title="{$expaltext}" /></div>
<div><strong><a href="{$forum_url}">{$forum['name']}</a></strong><span class="smalltext">{$forum['description']}</span></div>
</td>
</tr>
</thead>
<tbody style="{$expdisplay}" id="cat_{$forum['fid']}_e">
<tr>
<td class="tcat" colspan="6">
<table cellpadding="0" cellspacing="0" border="0" align="left">
<tr>
<td width="458"><span class="smalltext"><strong>{$lang->forumbit_forum}</strong></span></td>
<td width="85" align="center" style="white-space: nowrap"><span class="smalltext"><strong>{$lang->forumbit_threads}</strong></span></td>
<td width="100" align="center" style="white-space: nowrap"><span class="smalltext"><strong>{$lang->forumbit_posts}</strong></span></td>
<td width="200" align="center"><span class="smalltext"><strong>{$lang->forumbit_lastpost}</strong></span></td>
</tr>
</table>
</td>
</tr>
{$sub_forums}
</tbody>
<tr>
<td style="background: #000;height: 6px; " colspan="5">
</td>
</tr>
</table>
<br />]]></template>
        <template name="header_welcomeblock_guest" version="1413"><![CDATA[<div style="float: right;margin-left:8px"">
<img src="images/peaceblue/avatar.png" style="width: 64px; height: 64px;" />
</div>
<span style="padding-top: 10px;">
                <span style="font-size: 13px;">{$lang->welcome_guest}</span> <br /><a href="{$mybb->settings['bburl']}/member.php?action=login">{$lang->welcome_login}</a> &mdash; <a href="{$mybb->settings['bburl']}/member.php?action=register">{$lang->welcome_register}</a></span>
</span>]]></template>
        <template name="header_welcomeblock_member_moderator" version="1413"><![CDATA[<li><a href="{$mybb->settings['bburl']}/modcp.php"><img src="{$mybb->settings['bburl']}/{$theme['imgdir']}/toplinks/modcp.gif" alt="" title="" />{$lang->welcome_modcp}</a>]]></template>
        <template name="forumbit_depth1_cat_subforum" version="1413"><![CDATA[<tr>
<td class="tcat" colspan="6">
<strong><a href="{$forum_url}">{$forum['name']}</a></strong><span class="smalltext">{$forum['description']}</span>
</td>
</tr>
{$sub_forums}]]></template>
        <template name="forumbit_depth2_cat" version="1413"><![CDATA[<tr>
<td width="55" class="{$bgcolor}" align="center" valign="top" width="1"><img src="{$theme['imgdir']}/{$lightbulb['folder']}.gif" alt="{$lightbulb['altonoff']}" title="{$lightbulb['altonoff']}" class="ajax_mark_read" id="mark_read_{$forum['fid']}" /></td>
<td width="400" class="{$bgcolor}" valign="top">
<strong><a href="{$forum_url}">{$forum['name']}</a></strong>{$forum_viewers_text}<div class="smalltext">{$forum['description']}{$subforums}</div>
</td>
<td width="85" class="{$bgcolor}" valign="top" align="center" style="white-space: nowrap">{$threads}{$unapproved['unapproved_threads']}</td>
<td width="85" class="{$bgcolor}" valign="top" align="center" style="white-space: nowrap">{$posts}{$unapproved['unapproved_posts']}</td>
<td width="200" class="{$bgcolor}" valign="top" align="right" style="white-space: nowrap">{$lastpost}</td>
</tr>]]></template>
        <template name="forumbit_depth2_forum" version="1413"><![CDATA[<tr>
<td width="55" class="{$bgcolor}" align="center" valign="top" width="1"><img src="{$theme['imgdir']}/{$lightbulb['folder']}.gif" alt="{$lightbulb['altonoff']}" title="{$lightbulb['altonoff']}" class="ajax_mark_read" id="mark_read_{$forum['fid']}" /></td>
<td width="400" class="{$bgcolor}" valign="top">
<strong><a href="{$forum_url}">{$forum['name']}</a></strong>{$forum_viewers_text}<div class="smalltext">{$forum['description']}{$modlist}{$subforums}</div>
</td>
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Este no es el código que uso actualmente, lo cambié algo...
[attachment=1251]Hola. Yo tengo un problema parecido. necesito que me ayuden por favor. Os pongo la imagen y vereis
la línea 1 , columna 948: Auto de referencia no coincide con la ubicación del documento [ ayuda ]

... eds/5631537809691061263/posts/default "/> <link rel = 'alternativo' type = 'text ... ^

la línea 1 , columna 27704: el contenido no debe contener el atributo imageanchor (2 veces) [ ayuda ]

... o.blogspot.com 'alt =''/> </ div> </ contenido> <link rel =' Ty respuestas ... ^

la línea 1 , columna 34358: título no debe estar en blanco [ ayuda ]

... 7.338-05:00 </ actualizada> <título type='text'> </ title> <content type='html'> <... ^

la línea 1 , columna 34750: el contenido no debe contener el atributo trbidi (3 veces) [ ayuda ]

... o.blogspot.com 'alt =''/> </ div> </ contenido> <link rel =' Ty respuestas ... ^

la línea 1 , columna 35439: El atributo título del enlace no debe estar en blanco [ ayuda ]

... t.com/2011/09/blog-post.html título "autor =''/><> NOMBRE Rafi </ name> <email> ... ^

Fuente: http://gan-ardinero.blogspot.com/feeds/posts/default

Por favor ayudenme a solucionarlo