My fourth disc of my FireFly boxed set PLAYED fine, but had so many read errors that not even my VERY TOLERANT combo drive downstairs could rip all the way through it. Looking at it in the light revealed a slight discoloration in the substrate. Who knows if that was the problem or not... but I returned it and got another that ripped JUST FINE.
It just happens sometimes. Take it back to the store if you got it recently, otherwise... uh... oops?