There is a bug in multiMAN versions 02.07.01 - 02.08.06:
If you create a backup of a PS3 Game with the above versions, they won't work. The disc-layer encryption is still present, makes EBOOT.BIN and some other files unrecognizable to the PS3 (encrypted).
I'm trying to figure out how to resolve the issue to keep the same functionality. Curently it is either
1) play PSX games + rip blu-ray movies,
2) have backup of PS3 games working
In the worst case I'll create a standalone app (a simple PSX icon in your XMB Game column) which you can use to launch PSX games, so it won't require multiMAN at all.