Getting KHBBS to work on my PSP

My PSP uses homebrew 5.00 M33-6 ver. Trying to get the file to work but to no avail. I leave the .iso in my iso folder and tried to install the data thing but the PSP says that the game can't be started (80020321). can anyone shed some light on this situation? I searched through previous threads but no info for my specific problem.

Update to 5.50 Gen D3 (think that is the latest). Works fine on my brother's PSP.