Are you running any extensions/add-ons with firefox at all? I had a problem with one of mine, but it was a while ago. You may want to check your security settings as well, sometimes those will prevent things from working correctly.
"There's a box of Twinkies in that grocery store. Not just any box of Twinkies, the last box of Twinkies that anyone will enjoy in the whole universe. Believe it or not, Twinkies have an expiration date. Some day very soon, Life's little Twinkie gauge is gonna go... empty."