Just wondering why my saved file keeps on corrupting in the game called Summon Night DS Twin Age?

I tried to put it on FRAM32Kbytes, then FLASH12Kbytes, but none of these two seems to work fine. It couldn't load the saved file, to which NDS-Cartridge Back up media should I save the file? That it won't be corrupted...

Waiting for your response, thanks.
I read some thread regarding this but I didn't find it helpful...
and I am hoping that someone in the forum could help me sort this thing...
Thanks