NEC ND-3520A writes DVD's, which it cannot read

[Ruut]

The DVD's are datadisks which contain AVI's (XviD) were burnt from an image.
Curious about it is that the same disks CAN be read with another reader (Toshiba) in the same computer with no problem at all. Also the image can be mounted perfectly with DAEMON-tools.

The NEC-drive has the latest firmware (3.07) and is installed as master in the Secondary IDE channel.
Software used was Nero 7, latest version at a reduced speed of 12x (16x is maximum), verify was ON: Burn succesfull according to Nero. DVD's are RITEK F16.
From the 10 (different) discs that were burnt 5 cannot be mounted by the NEC-drive, the other 5 can; all 10 can be mounted (and played) with the Toshiba-drive.

Does anyone have a clue what is going on here?
Any help is much appreciated!

[budz]

use better quality dvd media like VERBATIM & TAIYO YUDEN. RITEK is crappy media which is why you're getting compatibility issues. Also use CDBURNER XP BURNER to burn DATA discs.

http://www.cdburnerxp.se/download.php