adding a banner breaks the script

hello,

(i'm putting this here because the site is in php with a mysql database).

i bought a yellow pages directory type site which already has google adsense on each page and i'm trying to add another banner or substitute it for a same size adsense but every time i try it breaks the script.

i've been trying to add


<a href="http://www.medi-vet.com/affiliatewiz/aw.aspx?B=4306&A=56&Task=Click" Target="_Top"><img border="0" src="http://www.medi-vet.com/affiliatewiz/aw.aspx?B=4306&A=56&Task=Get" alt="Low Prices & Free Shipping!" width="468" height="60"></a>

in the following code where indicated.


<div id="bg">

<div id="page">

<div id="content">



<div class="post">



<br><center><? echo $_SESSION[googlecode1] ;?></center>



<h2 class="title">Choose A State Below</h2>

<div class="entry">

<table width="723"><tr><td width="280" valign="top" align="center"><p><img src="<? echo $_SESSION[disurl] ;?>/files/logo.gif" border="1"></td>

<td width="468" align="center" valign="top">

<p><? echo $_SESSION[paragraph] ;?>



<p><? echo $_SESSION[googlecode2] ;?></p>


HERE



</td></table>



<table width="100%"><tr><td><strong>Choose A State:</strong></td>

<td> <?=state_dropdown();?></td>

<td><strong>Search For A Business:</strong></td><td><?=search_box();?></td></tr></table>



<p><?=get_states();?></p>

</div>

</div>

</div>



i'll gladly pm full details to any kind soul who can show me where i'm going wrong.

thanks, Pete.

 

Place it under the </td></tr></table>

(online one line down, i think that works)