Nostalgia save error

every time i save and turn the game off, it tells me that the save file is broken and i have to go to a previous one, does anybody know how to rid of this problem

what card/firmware

R4 upgrade

Take a look in the Common Issues thread.
https://www.romulation.org/forum/index.php?topic=1462.0Update your firmware, if that doesn't work, arm7 patch, etc.