tedster - 4:21 pm on Dec 26, 2010 (gmt 0)
The first thing to do when you want cross-browser functioning is to make sure your mark-up is valid - use W3C Validator for HTML [validator.w3.org] and W3C Validator for CSS [jigsaw.w3.org]. You can make yourself quite crazy trying to work around error correction routines which are not standard accross browsers.
At any rate, in your case there is a missing </a> tag in the advertising div just before the problematic footer area. That's where I'd start, in the HTML itself rather than the CSS.