Hard to explain so here is the problem: http://www.givetoagiver.co.cc/about.php
I think it's to do with the position property of the #content and #left/#right divs. Thank you in advance.
Add zoom: 1;
and overflow: hidden;
or overflow: auto;
to the content div.
When you use float for elements. The elements are kept out of the normal flow of the document.