Did you still have the original ISO you downloaded for the DVD5 version?
Of course not, would be too good, I always delete my isos when I tested the game and it's working.
or did you just create the copy you tried from the scratched disc? If so then I would expect it to also fail as it is copying it exactly, including the errors in the scratched area.
Yeah, that's what I tried, and the copy finished without errors, but doesn't work.