[whych]

All I can think is that the disc is not big enough or not totally campatible with the drive.
I have found that k3b is usually quite reliable. (Better than windows burning software). Maybe the media is the problem and not k3b, so try a different make of cd - I haven't had a problem with disks from Ald or Lidl and they are reasonably cheap.
I don't think the drive is a problem.
Try again with brasero and see if you get the same error.
Also check the iso is not corrupt.

(For a translator, use translate.google.com - it's pretty good) and post in both German and English in case something gets messed in the translation.)