Hi elkay,
it was not me - the guys at
www.konsolenfreaks.de did the job. i've sent them my ps2 along with some dvd-r i've burned. they tested those dvd-r in their own PS2 - didn't work. they checked the dvd-r with a PC - seems ok - but also seems that my superdrive laser writes a little uncorrect... they adjusted the laser in my PS2 so that i'm able to read originals and even my burned dvd-r.
now everything works perfect. i choose 'copy' in toast 5.2 under os x 10.2.2 - insert original - click 'burn' or make image (both ways work) and insert a dvd-r. ready for takeoff!