I can tell by a quick look at your site that it is not the updated css. See the gap underneath the menu tabs? That gap would not be there if you have the updated css in place. There are several other places in the css that changed from RC3 to 2.0 so its important to use the updated version of it. Try creating a new style and grab the css from here and set the forum to that and see how it goes. Ive a busy day and am off to the airport now. Will check back in when I can.