Urgent help: I485 denied !

I got a denial letter for my I485 which was filed in June 2005 based on my hu*****and's approved I140 (EB1B,approved in Dec.2004). The listed reason is non-available of visa. How is this pos*****le? Have they made a mistake? Has anybody had the same experience? My hu*****and filed his I485 in Dec 2004 and has not received any update yet. Can anybody give me recommendations on what I can do? I am really upset.