CSS div problems

So I’m working on an email for work and they want it done in css but I’m having problems. It’s a two column with header and footer. The right div seems to drop straight to the bottom off the left div, but it keeps to the bottom right --does that make sense? It looks fine on mac FF and Safari, but does this on IE5/Mac and IE/Win. Is there something wrong in my code or do I need to use one of those hacks that I have no idea how to implement? Here’s the link: http://www.shofnercreative.com/AndysPage/email.html

Thanks in advance for any help!