The nerdy answer...
http://en.wikipedia.org/wiki/Cyclic_redundancy_check
The lay answer....
A "CRC" error is most often caused by bad media - it could be any of the following:
1. A dirty disc,
2. A scratched disc
3. A poor quality disc (cheap media if it happens during the "Burn" section of your work)
4. A bad disc from the Mfgr.
It can also be from a bad optical component in your drive. At this time I don't believe it's your drive at all.
If you recently purchased this disc new from a store, I would return it as defective if just cleaning and the proper use of DVD Decrypter doesn't get the job done.
hmm I got it from the ad agency I deal with at work so it's possible that it's scratched. Thanks for the info guys!