It is probably a duplication in your favourite forums (under Preferences) that is causing the problem. If you remove all the duplicate favourite forums it should sort itself out.
I just looked in the database and your favourite forum list is being duplicated (so you have two entries for each forum).
I can remove them all and you can add them in again, or you can see if you can remove them from the preferences (or My Profile) link at the top of the page.
