Help with how to copy a already copied dvd

My friend backed up his dvd's with both xcopy and shrink. I wanted to copy one so I fired up shrink and get cycle redundency error. I tried all 70 of his dvd backups with same error with shrink on 2 pc's. I then tried dvd decrypter and get io error. ALL dvd's that error out play fine just cant be copied. He brought them home and copy fine. I am lost and clueless. This is on 2 pc's with 2 different dvd-r drives