set the appreture ring on the lens to A position, problem solved.. you must have moved it away from that position.
on the second note, are you sure about the lens name?? FA*50 never ever heard of it...
BR
ter
Just last night I was at a party and I watched a Nikon shooter fiddling with her camera in frustration, wondering why she couldn't shoot and what fEE meant... (yes, I helped her out).