HTML Code:
<!-- begin tren_z header-->
<div align="center">
<table width="785" border="0" align="center" cellpadding="0" cellspacing="0" class="border">
<tr>
<td align="left" valign="top">
<table width="100%" border="0" cellpadding="0" cellspacing="0" align="center">
<tr> <a href="index.php?s=...">
That last line might be your problem, you need to edit a template to remove it.
There should be a hash in the URL, (vB seems to be stripping it out for some reason) it will be something like
$session[...] in the template, so that is what you will need to look for.
('...' is just a filler for some words which I can't remember exactly)