[PSP] Error code

I hacked my psp phat (6.20 PRO-B9) and I can perfectly play downloaded games on it.
I also downloaded Rock Band: Unplugged, but every time I try to open it it says You can't start this game (80010087).Error code 80010087 = The psp can't find the UMD.Of course it can't since it's hacked.Can someone help me fix this?Thanks in advance!

Before you boot the game, press the select button. What is the UMD ISO MODE?

Replying to #2

InfernoEDIT: I tried all 3 Iso modes but none of them worked (Inferno, Sony NP9660 and M33 driver).

Weird...
PS: form which region is the ISO?

Replying to #4

It says Rock Band Unplugged Demo

NTSC or PAL?

Replying to #6

Demo --'Probably PAL.

It does matter. The USA roms/demo's I put on it don't show up and the EUR version does...
Anyways, can you download another fresh copy of the rom somewhere. Maybe it is damaged