By definition betas are experimental so you should expect various add-ons you may already have to break unless they have been updated for that particular beta. Don't hold your breath either. Ahead there may be a b3, a b9 and so on. Go back to 1.0.6. Wait for the 1.5 Final plus a few days more for Extensions developers to catch up--and even by then they may not all have. With Firefox it's always wise to wait.