Revise el plugin, O.O no aparece ninguna parte de alguna plantilla...
Sí sale... Porque si mal no recuerdo, yo lo había editado. xD
edite el plugin aca se los dejo

Código:
<?php
/*
*
** HP / MP / EXP Mod
*
*/

// Add The Hooks For the functions
$plugins->add_hook("postbit", "hpmpexp_postbit");

// Plugin Info
function hpmpexp_info()
{
    return array(
        "name"            => "HP / MP / EXP Statistics",
        "description"    => "Adds a RPG Stats Counter to the postbit.",
        "website"        => "http://ryan.mybb-templates.com/",
        "author"        => "Ryan Ashbrook",
        "authorsite"    => "http://ryan.mybb-templates.com/",
        "version"        => "1.0.0",
    );
}

// Activate The Plugin
function hpmpexp_activate()
{
}

// Deactivate The Plugin
function hpmpexp_deactivate()
{
}

function hpmpexp_postbit($post)
{
      global $mybb, $db;
      $post['postnum'] = str_replace($mybb->settings['thousandssep'], '', $post['postnum']);
      $daysreg = (time() - $post['regdate']) / (24*3600);
    $postsperday = $post['postnum'] / $daysreg;
    $postsperday = round($postsperday, 2);
    if($postsperday > $post['postnum'])
    {
        $postsperday = $post['postnum'];
    }
    $rpglvl = $post['postnum'];
    $level = pow (log10 ($rpglvl), 3);
    $ep = floor (100 * ($level - floor ($level)));
    $showlevel = floor ($level + 1);
    $hpmulti = round ($postsperday / 6, 1);
    if ($hpmulti > 1.5)
    {
        $hpmulti = 1.5;
    }
    if ($hpmulti < 1)
    {
        $hpmulti = 1;
    }

    $maxhp = $level * 25 * $hpmulti;
    $hp = $postsperday / 1;
    if ($hp >= 1)
    {
        $hp = $maxhp;
    }
    else
    {
        $hp = floor ($hp * $maxhp);
    }
    $hp = floor ($hp);
    $maxhp = floor ($maxhp);
    if ($maxhp <= 0)
    {
        $zhp = 1;
    }
    else
    {
        $zhp = $maxhp;
    }
    $hpf = floor (100 * ($hp / $zhp)) - 1;

    $maxmp = ($daysreg * $level) / 5;
    $mp = $rpglvl / 3;
    if ($mp >= $maxmp)
    {
        $mp = $maxmp;
    }
    $maxmp = floor ($maxmp);
    $mp = floor ($mp);
    if ($maxmp <= 0)
    {
        $zmp = 1;
    }
    else
    {
        $zmp = $maxmp;
    }
    $mpf = floor (100 * ($mp / $zmp)) - 1;

    $showlevel = my_number_format($showlevel);
    $maxhp = my_number_format($maxhp);
    $hp = my_number_format($hp);
    $maxmp = my_number_format($maxmp);
    $mp = my_number_format($mp);

    $post['user_details'] = "{$post['user_details']}<br /><br /><span class=\"smalltext\">Level: {$showlevel}</span><br />
<span class=\"smalltext\">Puntos: {$hp} / {$maxhp}</span>
    <table width=\"60\" class=\"rpg1\"  cellspacing=\"0\" align=\"center\">
        <tr>
            <td class=\"rpg2\" nowrap=\"nowrap\"><img alt=\"{$post['username']}'s HP\" src=\"images/rpg/bhg.gif\" width=\"{$hpf}%\" height=\"8\" /><img alt=\"{$post['username']}'s HP\" src=\"images/rpg/bhb.gif\" width=\"1\" height=\"8\" /></td>
        </tr>
    </table>
<span class=\"smalltext\">Nivel Maximo: {$mp} / {$maxmp}</span>
    <table width=\"60\" class=\"rpg1\" cellspacing=\"0\" align=\"center\">
        <tr>
            <td class=\"smalltext\" nowrap=\"nowrap\"><img alt=\"{$post['username']}'s MP\" src=\"images/rpg/bmg.gif\" width=\"{$mpf}%\" height=\"8\" /><img alt=\"{$post['username']}'s MP\" src=\"images/rpg/bmb.gif\" width=\"1\" height=\"8\" /></td>
        </tr>
    </table>
<span class=\"smalltext\">Actividad: {$ep}% </span>
    <table width=\"60\" class=\"rpg1\" cellspacing=\"0\" align=\"center\">
        <tr>
            <td class=\"rpg2\" nowrap=\"nowrap\"><img alt=\"{$post['username']}'s EXP\" src=\"images/rpg/bxg.gif\" width=\"{$ep}%\" height=\"8\" /><img alt=\"{$post['username']}'s EXP\" src=\"images/rpg/bxb.gif\" width=\"1\" height=\"8\" /></td>
        </tr>
    </table>";
}
?>
Es aquí:

Código:
$post['user_details'] = "{$post['user_details']}<br /><br />

Creo que habría que cambiar lo de $post['user_details'] y lo de {$post['user_details']}
Pero bueno, no sé PHP así que no estoy muy seguro de por qué cambiarlo.