If the magazine DVD is damaged, you can request a new DVD. Look in your magazine (impressum or within the article) how to contact them.

By the way, if a DVD has read errors you cannot get a DVD without read errors if you make a copy of it. Did you test the DVD with the cheatcode?
Code:
knoppix testcd
Write this in the early startup behind "boot:" in the left bottom corner. Knoppix tests the checksums of the whole DVD.