http://72.34.44.152/~gazrealt/comingsoon/home.html

You will notice that in IE, it looks fine. But in Firefox, the main text area extends way over the boundaries of the layout. The layout doesnt "stretch" like it does in IE.

I have no idea why... but it seems to have something to do with the three nested DIV tags. Any help would be appreciated.

Actually problem is the other way around.
Firefox and other Non-MSIE browsers renders the page right, and it looks weird because it has errors.

That web site is created for MSIE (most probably), and not tested on other browsers.

Check this site out: http://positioniseverything.net/explorer.html
:D

IE displays what you wanted to code, Firefox displays whay you've actually coded. In other words if your markup is wrecked, Firefox will let you know because of a very strict parser in Gecko based browsers.

Run your site through the validator @ http://validator.w3.org and see it's results for mistakes in your markup. This won't save your day, but at least gives you a proper image of what you've done wrong.