As floatingDivs said, your code structure is kind of odd.
Not sure why you need to use all that positioning at all. And you aslo placed <div id="content"> below everything, yet want this div with its backgroundimage to contain everything above it in the code, when really it should wrap around those elements.
I worked on a rework earlier, but got sidetracked and cant get back to it now. But we've given you some things to think about.