Errors seen on firefox:
Images being replaced with text. For instance the green dot next to the username signifying the user is online is replaced with text saying ":Username: is online". Arrow at the end of each thread name signifying a jump to the last post is replaced with text saying "go to last post" ... etc.
In Internet Explorer these images are also missing, but text is also missing. The links are therefore invisible in IE, but the link box is still there if you hover over the area where it should be. Perhaps its how internet explorer handles missing images.