Displayed different in IE and FF
 

Hi !

I got a banner on my forum index. It should look like this (and does in Mozilla FF):
http://www.deorvanheemskerk.nl/bugs/banner_ff.JPG

But in IE7 and 8 it looks like this: (floating above)
http://www.deorvanheemskerk.nl/bugs/banner_ie.JPG

It controlled with this code

And a similar problem is going on with the background image of the board.
Mozilla FF:
http://www.deorvanheemskerk.nl/bugs/bg_ff.JPG

IE: (no image)
http://www.deorvanheemskerk.nl/bugs/bg_ie.JPG

Controlled with the code in Main CSS, part BODY:
HTML Code:
#ffffff url(http://www.deorvanheemskerk.nl/images/bg_body.gif)
How does this have to change in order to work correctly in both browsers?
Greetz,

Tijmen