Can no longer burn DVD's


I have a PowerMac G4 with a Pioneer DVR-103 DVD-R/RW. I've been using it happily ever since I bought it. Just recently I was authoring a DVD out of DVD Studio Pro and it gave me a device error. Now nothing will work. I can't even burn data DVD's out of Toast. I can still burn CD's fine, and it read DVD's most of the time. I tried running the Tech Tools Pro driver test over it and it crashed the program. Now I'm out of ideas.
Yeah, I've tried several different brand's but there all the same. I was halfway through using a 50 DVD spindle of DVD's and the first half of them worked fine so I assume the media is fine.