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

<?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:

$post['user_details'] = "{$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.