the game freezes at all times during the game, I get sent back to the main menu, and get this error "

disc read error imagefile4, I called Playstion, we did a few things, and, I did get a bit further in the game, but, eventualy, it froze again.what can I do?, the disk is in near perfect condition, I took it to a gaming store to have it checked out, and the guy said, there isnt even a scratch