I didn't mention it, but when i run the backup cd in the dvd-reader, it works fine, but when it's in the CD-burner (which also is where it was installed from), it fails.
I've read tips on
this thread, handling the same subject, but i've still failed to create a PERFECT copy of the game (which works in all cd-readers/writers, or at least in all that the original cd works in).