The reason i said to go to gen-b was because people have had issues when lowering their firmware so thats why i never said m33... that and gen has been known to use their own saves.. don't ask why because i have never figured myself...
btw.. My tip still stands
EDIT: Try turning all other plugins off whilst trying and sounds silly but on some PSPs, the decrypted file turns up elseware... Maybe its an earlier copy used or what but sometimes have a look around.. Also note your "other copy" could of been a different region so the id of the save would have to be changed too with the decrypted save of course..