Diablo 2 Copy problem with CloneCD

[Bilange]

OK let me be brief. I use CloneCD to backup my CDs. The backup CDs works okay, except that Diablo asks me again and again to 'insert the diablo 2 game cd then press a key' when i try to play with the backup Game CD. So Whats wrong?? Oh btw its diablo 2 french.

Bilange