Activar FancyBox [no anda]

Hola, vengo con un pequeño problema, no puedo activar el plugin "FancyBox (1.0)", quisiera saber si alguien me puede ayudar.

Plantillas:

header_welcomeblock_guest:

Código:
<script type="text/javascript">

<!--

    lang.username = "{$lang->login_username}";

    lang.password = "{$lang->login_password}";

    lang.login = "{$lang->login}";

    lang.lost_password = " &mdash; <a href=\"{$mybb->settings['bburl']}/member.php?action=lostpw\">{$lang->lost_password}<\/a>";

    lang.register_url = " &mdash; <a href=\"{$mybb->settings['bburl']}/member.php?action=register\">{$lang->welcome_register}<\/a>";

    lang.remember_me = "{$lang->remember_me}";

// -->

</script>

<li><a id="userloginmenu" href="javascript:void(0);">{$lang->welcome_login}</a></li>

<li><a href="{$mybb->settings['bburl']}/member.php?action=register">{$lang->welcome_register}</a></li>

<li style="float: right;">{$lang->welcome_current_time}</li>

header:

Código:
<div id="container">

        <a name="top" id="top"></a>

        <div id="panel">

            <div class="wrap"><ul>{$welcomeblock}</ul></div>

            <script>

                $('panel_usermenu').observe('click', function() {

                    this.next('div').toggle();

                });

            </script>

        </div>

        <div id="popupLogin" style="display: none;">  

            <a id="popupLoginClose" href="javascript:void(0);">x</a> 

            <h3>{$lang->login}</h3>

            <div class="box">

                <form id="login_form"  action="member.php" method="post">

                <fieldset>

                <ul>

                    <li>

                        <label class="loginlabel" for="username">{$lang->username}</label>

                        <div class="loginfield"><input id="username" size="30" class="input_text" type="text" name="username" /></div>

                    </li>

                    <li>

                        <label class="loginlabel" for="password">{$lang->password}</label>

                        <div class="loginfield"><input id="password" size="30" class="input_text" type="password" name="password" /><br/>

                        <a href="member.php?action=lostpw">{$lang->lostpw_note}</a></div>

                    </li>

                    <li>

                        <input type="checkbox" value="1" name="remember" checked="checked" value="yes" id="remember" /> <label for="remember">{$lang->remember_me}</label>{$captcha}

                    </li>

                    <li>

                        <input id="login_submit" type="submit" value="{$lang->login}" />

                        <input type="hidden" name="action" value="do_login" />

                        <input type="hidden" name="url" value="{$redirect_url}" />

                    </li>

                </ul>

                </fieldset>

                </form>

            </div>

        </div>  

        <div id="backgroundPopup" style="display: none;"></div>

        <script>

            $('userloginmenu').observe('click', function() {

                $('popupLogin').toggle();

                $('backgroundPopup').toggle();

            });

            $('popupLoginClose').observe('click', function() {

                $('popupLogin').toggle();

                $('backgroundPopup').toggle();

            });

            $('backgroundPopup').observe('click', function() {

                $('popupLogin').toggle();

                $('backgroundPopup').toggle();

            });

        </script>

        <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 class="searchbox">

                    <form method="post" action="{$mybb->settings['bburl']}/search.php">

                        <input type="hidden" name="action" value="do_search">

                        <input type="hidden" name="postthread" value="1">

                        <input type="hidden" name="forums" value="all">

                        <input type="hidden" name="showresults" value="threads">

                        <input id="b-query" onfocus="if (this.value == 'Search...') {this.value = '';}" onblur="if (this.value == '') {this.value = 'Search...';}" type="text" class="textbox" name="keywords" value="Search...">

                        <input id="b-searchbtn" type="submit" class="button" value="Go">

                    </form>

                </div>

            </div>

        </div>

        <hr class="hidden" />

        <br class="clear" />

        <div id="content">

            {$pm_notice}

            {$bannedwarning}

            {$bbclosedwarning}

            {$unreadreports}

            {$pending_joinrequests}

            <div class="menu">

                <ul>

                    <li><a href="{$mybb->settings['homeurl']}"><span>{$mybb->settings['homename']}</span></a></li>

                    <li><a href="{$mybb->settings['bburl']}/search.php"><span>{$lang->toplinks_search}</span></a></li>

                    <li><a href="{$mybb->settings['bburl']}/memberlist.php"><span>{$lang->toplinks_memberlist}</span></a></li>

                    <li><a href="{$mybb->settings['bburl']}/calendar.php"><span>{$lang->toplinks_calendar}</span></a></li>

                    <li><a href="{$mybb->settings['bburl']}/misc.php?action=help"><span>{$lang->toplinks_help}</span></a></li>

                </ul>

            </div>

            <navigation>

            <br />

Espero respuestas, cualquier cosa pidan.

P/D: On. Turn FancyBox on and off. "Sí".