manual side solumn not working on showthread template

[rockon]

I'm adding a right column to pages that would be difficult to do custom with CMPS integration, e.g. showthread, and it won't work on my showthread template :S

This is what I've done:

Immediately below '$navbar':

<table cellpadding="0" cellspacing="0" style="margin: 0px; padding: 0px; width: 100%;">
<tr>
<td valign="top">




Directly in-between '$similarthreads' and '$footer':

</td>
<td width="200px" valign="top" style="padding-left: 8px;">

<div style="padding-bottom:8px;">
<table align="center" border="0" cellpadding="3" cellspacing="1" class="tborder" width="100%">
<thead>
<tr>
<td class="tcat" colspan="4">

<table cellpadding="0" cellspacing="0">
<tr>
<td>
<span class="smallfont"><strong>Advertisement</strong></span>
</td>
</tr>
</table>

</td>
</tr>
</thead>
<tbody>
<tr>
<td>
Content
</td>
</tr>
</tbody>
</table>
</div>

</td>
</tr>
</table>



The page to see what it shows is:

http://www.rockonpublishing.co.uk/showthread.php?t=12

Any ideas why it's not working? It works on other pages e.g.:

http://www.rockonpublishing.co.uk/contactus.php?

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Spelling error in title and...

For your aid, the table at the bottom of the showthread page saying "Advertisement" is what is meant to be in a cell to the right.