What does this mean and how do I deal with it?
See if this helps:
CRC (Cyclical Redundancy Check) errors don’t necessarily mean that the source media or files themselves are corrupt, but the errors do mean the data in the copied/tranfered/converted/whatever versions of the files does not exactly (bit-for-bit or Byte-for-Byte) match the data in original.
Anything involved in the chain of the copy process could be responsible for the errors; bad media, faulty drive-controller circuitry, bad RAM are all possible culprits.