that happened to me with my 256mb sd card. whenever i went to the photo channel with it it said corrupted files and i couldnt save anything in it. So i ahd to buy a 2gb sd card and its been good so far for both my wii and camera.
This happened to me too, I saved, turned off the wii, turned it back on, went to the Wii channel, went to the photo channel and picked SD Card then when all the pictures loaded I went back to the game and it worked.