did you just purchase the card. If you did send it back you have got a faulty card. i forgot to say are you picking the right save type?
have you got super mario bbros save set on epprom 64/512 kbit.
Capacitor inside is dead? What's that? Today I was playing Ace Attorney 1 and it suddenly freezed.. When I turn off and play the game again, the save is gone again... Same thing happened to Quendan 2... I thought everything was fixed after I upgraded the firmware T_T.Perhaps the capacitor inside (IIRC what is used to handle saves) is dead. I think something similar happened to a friend, except it was DOA >_>