Another "can't read dvds" cry for help

Ok... here we go... last hope.
I have an iMac, 17", 1.25GHz, 512Mb, 80Gb machine, running on OSX v.10.3.6. I am fairly happy even if there has been some issues with it. Both hardware and software issues. Now there is a new one. Since a few upgrades ago I seemingly can't read DVDs burnt on this computer (it is a PIONEER DVD-RW DVR-106D drive, using -R dvds). Yes, it did start after I had made an upgrade... i think... I am not completely sure since I didn't test it immediately after the upgrade was done but I have made several upgrades since then and but the problem stays. I have tested different brands of dvds but I can't read any of the dvds (cds are fine) I burn myself using this computer. The dvds run fine in any other player I have tested including other Macs and several PC dvd drives. I can play purchased dvd movies but not the ones I have made myself. When I insert a dvd (data or movie) the drive spins up a little... hesitates... tries a few times but then it quits and ejects the disc. What is the matter with this drive?? Numerous of times I have tried to look for an answer on the net but none has helped so far. I am a bit desperate and I hope any of you can help me find an answer to this.

i dont know what the problem is but im having the same one
any help would be appreciated

i'm having the same problem with the pioneer dvd-rw. i've checked other forums and many others have the same problem and list OSX 10.3.x as the current operating system. i'd like to upgrade to Tiger but can't even do that since the DVD reader won't work.

Have you downloaded the OS X 10.3.9 update?

Vicky