well, I don't have time to troubleshoot your code but your site looks ok in Firefox and Safari, so formatting issues Explorer related. I do notice that your inside pages have an extremely wide top navigation bar (1024 pixels) I'd highly recommend shortening it to a max of 800pix. Even with many people having hi-res monitors most people don't like opening up the browser window all the way, or reading such wide lines of text.
Your right hand advertising reserved space may be causing your formatting issues. Try putting in a graphic holding ad, or PSA, to reserve that space.