Hi,
I would recommend you to follow the Installation Guide :-
Installing the Avaya S8800 Server for Avaya Aura™ Communication Manager located at following link:-
http://support.avaya.com/css/P8/documents/100089493
and Installing and Configuring Avaya Aura™ Communication Manager located at following link:-
http://support.avaya.com/css/P8/documents/100089133
Before installing CM 6.0, installation of System Platform is a Must.
So, I hope you are installing System Platform properly.
Once this is done you can follow the above link to install the CM6.0.
If you still face the issue, I would recommend you to contact local AVAYA installation team.
Thanks.