I'm getting an error "load rom error=-1"

So, I've downloaded a few games (Mario Kart, Animal Crossing, Metroid Prime Hunters and Pokemon Black) and they were working perfectly fine for a few days, no problems at all. But then after playing one of the games, and saving and quitting, I came back to play again and I got that error, same with all the games. I can't play anything except for Lameboy which is a gameboy emulator.Any help?

possibly format the card,
and start over,
there may just be errors on the micro sd card,