It's not the table element at all. It's exactly what the error says - the element isn't allowed there. If you look right before the table, you'll see you closed a row:
HTML Code:
</tr> <!-- / guest welcome message -->
<!-- top -->
<table class="forumbit1" width="100%" border="0" cellpadding="0" cellspacing="0">
Things in a table may only go between <td> tags. Somewhere along the way, you either dropped the next row tags or else you forgot to close the table.