My smart media shows error?

Hi, i have a mini digital recording studio made by a company called zoom, the studio uses smart media for the memory. I have several cards with no problems but i recently bought a higher memory card which worked ok for a short while, but now when i insert this card into the studio, it shows up as error. I have tried gently wiping it clean, but no difference. The card is well protected and not damaged, so is there anything i can do?