Divs shifted in IE6

I'm having some issues with the output in IE6.
The website is running the latest Wordpress, and the code is XHTML & CSS3 valid. However, whenever I open the website in IE6, the navigation panel on the right is shifted down quite a lot. I don't understand why this happens, because the navigation works fine in IE7 and IE5.

Any help would be much appreciated.

The site is http://www.fingalcc.ie
And here is the site at browsershots: http://browsershots.org/http://www.fingalcc.ie/

Perhaps you can use a hack in order to properly position the navigation panel? For instance, I have to use the following hack in order to properly position the navigation pane of my website

You may both want to read this:

http://www.gunlaug.no/contents/wd_additions_16.html

Thanks for the replies. I managed to fix the problem without sending IE into Quirks mode, at least I don't think I'm doing that...

I rewrote the CSS for IE and replaced any PNGs with GIFs (if rendered in IE <7 ) and that seems to have fixed the problem of the shifting Divs.