Alert This software cannot be installed on this computer

Hello,

I have a Imac G5 PPC, 1.8 GHZ. After having some issues with the computer starting up, I decided to erased the HD with the Zero out Data option so I can reinstall with the OS disks that I have. My computer came with 2 disks that are gray that state - iMAC G5 Mac OS X Install Disc 1 - Mac OS version 10.4, AHT version 2.5.1, Disc Version 1.0 and the second disc reads Mac OS install Disc 2, includes Mac OS 9.2, Disc Version 1.0.

The issue I am having is after erasing the HD, when I boot from the install disc 1, I get prompted to select a language, after I select it, I get the preparing to install screen then a box opens that states, Alert This software cannot be installed on this computer. It give me the option to "Restart" or "Startup Disk"...

When I select either the results are the same. It just continues to produce that same exact outcome. Help!