Try another PS2 game (not a import).... See if that backup will boot with the burning methods you have listed....
I need to do some research to find out if the Neokey/Sbox will even boot import games....Cause I'm not sure if it will or not...
If you burn another PS2 game and it works, it may be because it won't boot imports....
I'll find out for sure and let you know....