Diablo II (backup) install problems...

[Maketty]

Hello, I have a backed up copy of Diablo II it used to work fine on my system, but now when I try to install it: I insert the install disc, choose full install, enter my name and my cd-###, then click ok, it immediately tells me it needs the disc labeled 'play disc' I insert my copied 'play disc' and click ok, the cd drive whines like the install is going to ####t and then goes quiet... the install just sits there trying to read d2char.mpq! I know my cds aren't damaged, I take perfect care of them, and I cleaned them right before trying to install, can anyone help me? I would really appreciate it!!!