DVD photo library backup (iphoto 5) shows "no photos"

[hakunamatita]

I have an iMac g5 17" running OS 10.4.3 and iPhoto 5.0.4 (263).

I have made DVD archive backups of my iphoto library using the "Burn" feature of iPhoto.

Here's my question: Is there something wrong with using DVD-R "Data" discs (brand: KHypermedia)?

After burning one of this type DVDs, and reinserting the DVD, iPhoto recognizes an iphoto library, but shows "no Photos" and "(0) pictures in the Source list for that DVD.

I burned a second DVD and it did the same exact thing.

I burned a third DVD using the same process in iPhoto of a different brand (I don't know what type DVD or what manufacturer), and it worked correctly.

Is my problem the "Data" discs, the KHypermedia brand, or something else?

Thanks!