I figured out my problem.

It was the quick reply hack.
The Quick Reply Box:
In the "showthread" template adding the $replybox right after the following. I had it placed in my own area, I think it was even before. Reverting "showthread" will make it work or cutting and pasting the reply box variable as indicated by the instructions

. And the way to test it is to select outside the box before hitting submit. If the cursor is in the box you do not get the error.
In the "showthread" template add $replybox right
AFTER the following:
<!-- first unread and next/prev -->
<table cellpadding="2" cellspacing="0" border="0" width="95%" align="center">
<tr>
<td><smallfont>$pagenav </smallfont></td>
<td align="right"><smallfont>
<img src="https://vborg.vbsupport.ru/images/prev.gif" alt="" border="0">
<a href="showthread.php?s=$session[sessionhash]&threadid=$threadid&goto=nextoldest">Last Thread</a>
<a href="showthread.php?s=$session[sessionhash]&threadid=$threadid&goto=nextnewest">Next Thread</a>
<img src="https://vborg.vbsupport.ru/images/next.gif" alt="" border="0">
</smallfont></td>
</tr>
</table>
<!-- first unread and next/prev -->