DVD Drive having trouble recognizing ISO Data CDRs

[audiodrome]

I just burned a bunch of ISO Data CDRs and when I began inserting them back into the drive to catalog the file information the drive did not recognize any of the discs. Now this has happened to me a few times before so I knew just what to do. I took an ISO Data CDR that I had burned a few years ago (a different brand of CDR) and inserted it into the drive and sure enough it recognized it and opened a new window with all of the folders. After that the drive was able to recognize all of the newly burned discs, and like I said this has happened to me a couple of times before. What's going on here? Is this some sort of irrational computer "buggy" thing or does it mean that these new discs are "bad" burns?

Note: This never happens with audio CDs or audio CDRs

[Ian]

Could be bad quality discs, bad burns or a combination of the two. Can you read them in other drives?