So day two has come and gone on building an HTPC out of the PPC Mac Mini. I burned two different versions of OSX 10.4, one .iso and one .toast. The .iso wouldn't boot, and the .toast burned, but gave errors and wouldn't pass verification before install. I installed anyway, and became stuck in an endless loop that would not allow me to remove the DVD from the drive. So I researched how to burn a .toast without a Mac, and came up with this posting which said to use InfraRecorder and make sure session-at-once was used. Once I had a good version, I removed the four screws on the top of the DVD drive (with the machine turned off, of course) and manually replaced the bad DVD with the good one. The good DVD install passed verification with flying colors, and about 30 minutes later I had a fully functioning OSX system.