I was surprised when my backup didn't work but even more so when the original didn't either

It hangs on the loading screen for the very first level.
The only thing i can think of is the game is detecting a mod chip and refusing to play the game. I'm using a V4 PS2 which is fitted with the Neo4 chip, never had this problem before with any other game, original or back up.
Anyone got this game and are running it successfully with a modded PS2 ?