Superdrive DVD+RW problem?

Well, I have searched the forums and found others with the same problem, but nothing for a solution. I dug out some movies I recorded a few years ago with my Phillips home dvd recorder that I dubbed off old VHS, and was going to rip them so I could clip some things out and make a new movie, but they dont work right. They play fine in any home dvd player and they play fine on my older iBook G4 with combo drive; however, my new iMac C2D and my Powerbook G4 (both with superdrives) first try to open Toast, as if they were blank DVD's, and if I close Toast it ejects the DVDs. So I turned off Toast in the system prefs so that it wouldnt automatically load, and now when you insert the DVDs nothing happpens. It takes them in, but doesn't mount them, nor can I play them thru DVD player, Imovie, Idvd, QT, Final cut, etc. It is as if they are not there. Handbrake kind of senses that something is there in the rdisk place, but wont do anything with it. I can eject them with the F13 key, but that's about all either system will do with them. What is the secret to get them to play? They have all been finalized and work great on any computer or dvd player I have except the two superdrives. Is there some trick I need to do somewhere to make them accessible as a regular DVD? These are DVD+rw 4.7GB 4X dvds. Both Macs are fully updated with Tiger 10.4.8, all flashes and firmware updates, etc. Both superdrives will read commercial DVDs, CDs, CDRWs, and write DVDs and CDs just fine, just wont playback these previously burned ones. Help!

My new powerbook is having problems with DVD+RW's also, while all my computers do wonderful with DVD-RW's. So it's definitely a problem with the new drive that is put in.. which kind of annoys me