It's rather difficult to guess why since the error does not give any more information, but there are a few things you can try. First, if you are installing from a CD, try downloading the installer to your desktop first and then run it. CD-ROMs can sometimes run slower that the installer and this can cause problems. Also, check to see what other NI software may have been installed on this machine and determine if any of it could conflict with the 6.0.2 Run-Time Engine. Just possibilities but hopefully they can get you going!
J.R. Allen