Hello Joe, and a warm welcome to the forums! 🙂
OK, This is the retail dvd. That means it will install on ANY Mac with a G3, G4, or G5 ppc processor along with Xcode 2. (256 megs of RAM min)
The dvd is black with the X on it and has this number on it - 2Z691-5305-A
And possibly... 2Z691-5811-A is the Install Disk for PPC Macs, G3, G4, and most G5s, but we need to know the exacyt G6... I think the latter might be for the later Duals & Quads, but not certain.
"Disk Utility
1. Insert the Mac OS X Install disc that came with your computer, then restart the computer while holding the C key.
2. When your computer finishes starting up from the disc, choose Disk Utility from the Installer menu. (In Mac OS X 10.4 or later, you must select your language first.)
Important: Do not click Continue in the first screen of the Installer. If you do, you must restart from the disc again to access Disk Utility.
3. Click the Erase tab.
4. Click the disclosure triangle to the left of the hard drive icon to display the names of your hard disk volumes and partitions.
5. Select your Mac OS X volume, then choose MacOS Extended Journalled.
6. Click Erase & look for Security Options. choose Zero 1 pass."
Hopefully then you can install.
Formatting & Partitioning a Hard Drive in OS X - Tiger and Leopard...
http://www.kenstone.net/fcphomepage/partitioningtiger.html