(1) When you post code in a message, please enclose the code within [noparse]
[/noparse] tags. Doing so allows the code to retain its formatting which makes it much more readable. It also puts the code in a scrolling box which does not take up as much vertical space in the post.
Please click the link in the bottom of my post and read our instructions for posting code.
(2) Can you please post a screen shot showing how the page is supposed to look? We cannot see the images and the code does not include image sizes so we cannot "roll our own" to fit the space. A full rez screen shot would help.
At first glance, the use of positioned elements is probably throwing a monkey wrench into the layout of the page. The hefty margins, some negative, support that probability.
If your code is on a server, a link to the site would be helpful, too.
Your code is impressively valid
Out of curiosity, why do you use IDs instead of classes?
This is a screen shot of how your code looks in Firefox to me. I added the blue background because the white menu letters were invisible against the page without a background image.