I have the same problem as of yesterday - there is just one message that I sent weeks ago that will not delete from the BB, it is not on the main FB account on the computer. It shouldn't be a big deal but that little icon showing me I have a FB message when I don't, really bugs me !!

I have done battery pulls, deleted and reinstalled the FB app and NOTHING works grrrrrr

Hope they get this figured out soon !!