Try deleting carbonite.lua and carbonite.lua.bak from your WTF/Account/<accountname>/<servername>/<toonname>/SavedVariables folder. You'll have to reset your preferences/options for carbonite for that toon, and you'll lose (I think) questing data (like which quests you've done).
Actually, you might want to just move those files somewhere else, so you'll still have them if this doesn't work.
