You have forgot the 2 closing div?s.
Try:
Code:
<div id="ads" class="tborder content_block">
<h4 class="thead block_title">
<a href="#top" class="collapse_gadget" onclick="return toggle_collapse('ads')"><img id="collapseimg_ads" src="$stylevar[imgdir_button]/collapse_generic{$vbcollapse['collapseimg_ads']}.gif" alt="" border="0" /></a>
<a name="ads"></a>
<span class="block_name">Ads</span>
</h4>
<div class="block_content" id="collapseobj_ads" align="center">
<table cellpadding="0" cellspacing="0" border="0" class="tborder" width="$stylevar[tablewidth]" align="center">
<tr>
<td>
<table cellpadding="$stylevar[cellpadding]" cellspacing="$stylevar[cellspacing]" border="0" width="100%">
<tr align="center">
<td class="alt1"><script type="text/javascript"><!--
google_ad_client = "pub-3010515223597560";
/* 200x200, created 16/09/09 */
google_ad_slot = "9446574801";
google_ad_width = 200;
google_ad_height = 200;
//-->
</script>
<script type="text/javascript"
src="http://pagead2.googlesyndication.com/pagead/show_ads.js">
</script></td>
</tr>
</table>
</div>
</div>