This might work.
Go to showthread template
look for
Code:
{htmldoctype}
<html>
<head><title>$bbtitle - $thread[title]</title>
$headinclude
<script language="javascript" type="text/javascript">
<!--
function aimwindow(aimid) {
window.open("member.php?s=$session[sessionhash]&action=aimmessage&aim="+aimid,"_blank","toolbar=no,location=no,menubar=no,scrollbars=no,width=175,height=275,resizeable=yes,status=no")
}
// -->
</script>
</head>
Make sure that the $headinclude variable is where I have it. If it's not put it in there. This is some times the problem and sometimes not. It was with mine when it wasn't showing up in the threads.