I understand there is a div for banner but its not really functional in Firefox since the banner overflows the title if using adsense for example. The problem does not persist in Firefox however. Placing the banner before the "banner" div is fixed it.

<div class="banner">
      <?php
if (module_exist("adsense"))
{
 print adsense_display("468x60", 2, 4);
}
?> 
    </div>