Strange DVD burning problems

We've been trying to backup a bit of data (all our pictures, our mpeg'ed music etc.) to DVD, but so far it's not behttp://www.blogger.com/img/gl.link.gifen all that successfull :( A while ago, I bought a LaCie DVD burner, but I have never been able to burn anothing but rewritable DVD media. I've tried with a few different write-only, but none of them ended up working. The drive seemed to burn them just fine, but when I tried to read the content of them on a different drive, it turned out to be just yet another beer coaster. When we bought Katrin's iBook, we decided to go for the model with a superdrive, specifically to replace the LaCie drive. Unfortunatly, it has exactly the same problem! :( It destroys all write-only discs but not re-writable ones... I haven't got a clue what the problem could be, so any help would be appreciated. UPDATE: It turns out that the while problem i a firmware issue!?! Apple has apparently messed up somewhere, and limited the drive in the iBook to only 2x speed. This doesn't play well with 8x speed discs for some reason, so those 100 discs we bought when we were in Canada is as good as useless. The only way we can use them, is by buying a new DVD-burner, or hope that Apple updates their firmware. Somehow, my respect for Apple dropped a few notches tonight...