PSP UMD ISO Issues -not PSX-

I'm trying to boot a Final Fantasy Tactics The War of the Lions.cso game but I'm still getting the 80020321 error, which means I need a UMD in the drive (there is one).

I'm using 3.40 OE-A so the software shouldn't be an issue...

The folder set up is as follows:

ISO- Demo ISO, Final Fantasy Tactics The War of the Lions.cso
ISOMISC- backpic (fastloader VO.7 image)
ISOSPLIT- empty
MP_ROOT-
MUSIC
PICTURE
PSP- GAME
SAVEDATA
COMMON
GAME150 - 1.0FW EBOOT MADE BY MODILLER
DEVHOOK
DEVHOOK%
FASTLOADER
FASTLOADER%
GBA
GBA%
ISO
ISO%
SNESEMU
SNESEMU%
SYSTEM
VIDEO



I'm not sure if it's supposed to be in a different place or if I need a specific program to launch it. I've tried placing it in the Game150-ISO folder and that hasn't worked either. I've also launched Devhook and tried to start it, but it doesn't give me an option to select it.

'any help at all is greatly appreciated. Be well.