Baked Alaskan: Do you have adblocks loaded? If so, try:

Tools > Adblock > Preferences > Adblock Options > un-check Obj-Tabs

(of course if adblocks is not loaded, you will not have that option)

You could also take a look at this which talks about what to do if Firefox stops working correctly. (I have not read it all yet, but hopefully it can help)

http://kb.mozillazine.org/Standard_diagnostic_%28Firefox%29