What type of error do you get?
I know for sure that copied cd's are harder to play, and might be in that case, the fact that your cd rom drive may be getting old, and so the laser might be getting dirty, etc.
I advise you try buying a laser cleaning kit, which comes with a cd with special brushes which you put a slight dab of cleaning liquid onto, and this cleans the mechanism. They aren't expensive, and might just prolong the life of the drive a little longer.
I hope this helps. Its definetly worth trying