Hi,

the Benq 1640 and the Plex 740 are identical hardware, only their firmware is different!

But still I am very sure that the problem is not caused by a defective media, my DVD is flawlessly right

Since you got a Dell PC, I doubt that the rest of our hardware is comparable, I have an Athlon XP64 on an Asus A8V Board. So it seems we have to make the drive (firmware?) or Knoppix responsible for that behaviour. Maybe one of the Knoppix developers can have a closer look?

cu,

Jackie