Problem ripping CDs

OK While using Nero 6 Enterprise edition as soon as I try to rip tracks from a CD an error comes up saying “error while reading. disc may be corrupt.” Yesterday I ripped the same CD and it worked perfectly but today I get that error then the program locks up. I have plenty of CPU power and a gig of memory. My CDDVD burner is a liteon 832S. Please help. :confused: