About my previous problem: I figured out that it was the USBD.IRX which caused the problem. On my first attempt I used an old version (24kb) which worked fine on my CDR-RC1-Disc. On the DVDRW RC2 I used a newer version (36kb GT4 I think) which didn't work. Replacing the file solved my problem. It is...

@MacBoehm: That's quite strange. Can you provide some more details? What kind of PS2 do you use, US, european, japanese? Which Modchip do you use? Do you have a memory card plugged in when starting scummvm? Is it a Sony or 3rd party one? Do you boot ScummVM directly or do you use additional program...

Well I tried the RC2 and I come only as far as the screen with the ones and zeros.
It won't do anything more.