Yes, as the last replier suggested, try reading the cdr in another drive. I've had numerous different CDRom's through the years, switching from ide to scsi a few years back, now I've gone back to ide again. I've also had a CD writer practically since they first came out. The thing I've figured out is that not all CDRoms read all CDR's. Scsi drives seem to do a much better job reading the various cd media's, so if you've got one, try it out. Also, as I've seen CDRoms start showing their age by first stopping to read CDR's that they previously could - then it's just a short time before the drive stops reading pressed CDs.
And then there's always the possibility that the cdr has gone bad. But atleast see if it is your drive first.