I don't think the new update likes firefox...
The messages once open look fine and when looking at the general forums list everything looks fine, its just when you get to where the threads actually are that is all messed up.
As others have said doesnt look anything like that on Firefox for me. Plus theres and Advert already on your screen as mine is just blank down the right hand side
also you guys the adblock plus helps :<). i hae my entire browser histery cach etc cleaned after each internet session and i dont have that look. Oh and i am using firefox 3.6 with adblock on.