"FILE NOT FOUND" error on some games

[satansgutter]

Hi i backed up the Simpsons Hit and Run and when i put it into my Chipped PS2 it was fine on the menus and starting up but as it when to play (when you get controll of the character) it came up with "FILE NOT FOUND" error. Although i copied my mates backed up version (copy to copy) of Hit And Run and that worked fine. Just wanted to know how to stop this in the future.

Thanks

d;-0