The page is pretty messed up, even in IE, and it's three times wider in my gecko-based browser, K-Meleon. My browser gave me this information for your unseen header image:
* I M A G E P R O P E R T I E S *
Viewing page source, I see:
img src="/images/full.png" width="1024" height="768" class="layout"
I would say that you don't have the full path to the image in your header.php for one thing, and you had better check the width and height properties?!?
As for the background image, I suspect it is covered somehow, something is in conflict besides the 404-compliant image. The whole thing, minis the content, repeats several times over. You should check it out in another browser too, try FireFox.