This same problem has happened to me today : trying to book a promo award flight to SXM and back...
and when I call FB, the ladies say there is nothing they can do... No availibility, no way of booking the promo internet tickets through them.
I also called the internet assistance and they say that FB has to help for the booking, since the glitch is not repaired yet..
I tried again FB sites (AF and KLM), and the problem occurs on both sites...