1) How old is your Playstation, it could be that it is getting on a bit??
2) Maybe your laser needs a slight tweak, I don't know how to do it myself, but this could be the reason, as the CDR is slightly different to an orignal Playstation disc.
3) Try playing the game with your Playstation at an angle or even upside-down!! May sound weird, but try it, it works!!!!
Hope some of that helps you,
Good Luck!
