ASUS A8N-SLI + Plextor PX-716SA SATA can't find filesystem

Hi.

Using the following equipment:
ASUS-A8N-SLI (non-deluxe)
AMD A64 3000+ Venice
MDT 2x512MB
2xSamsung SP2004C 200GB
Plextor PX-716SA (SATA Version)

Booting with Knoppix 3.6 works, but network interface not useable (module?)
Booting with Knoppix 3.8.1 & 3.8.2 (several CD's burnt...) fails always after device-Scan with the message:

Can't find KNOPPIX filesystem, sorry. Dropping you to a (very limited) shell. Press reset button to quit.

3.6 detects DVD-Burner as /dev/hda, drives as /dev/hde /dev/hdg (although drives are connected to first and second controller port) and mounts the DVD as /dev/scd0

Tried Gentoo 2005.0
Fails with (can't mount DVD-drive, but detects the Samsung SATAs as dev/sda /dev/sdb)

Any ideas?