I've tried burning it with Blindwrite using DAO Pw mode, which supposedly makes 1:1 copies of CDs. The copy does get past the CD check, but on my windows XP box, it will randomly generate a memory access error while playing the game. I also tried it on a windows 2000 box and it generates a similar but different error when one of the registers tries to access itself right as warcraft 3 is starting up. So I'm not exactly sure how to burn this one. Apparently Blizzard has figured out how to tell the difference between the real CD and copies made by Blindwrite. It seems kind of weird, though, that the copy protection generates memory access errors.
I have made a working backup of warcraft 3! I used CloneCD 18.104.22.168 with fast error skip ON and read the image file from my cd burner and it worked fine. misagh was you reading the image from your cdr drive or another cd drive?