Darwin won't install


This isn't *exactly* OS X, but its close. I can't boot into Darwin. Darwin is instaled within the first 8 gigs of the disk, but behind a small mac os install partition. The system disk utility seems to be a joke. You can sellect either OS, but you have to close it to reboot...(right?)
Open it again before re-booting, and mac os is sellected, no matter what you had sellected before. Re-booting while holding down the option key brings up a screen with a folder with a "?" mark on it, then it moves to a selection screen with one choice....mac os.

This is a dual 450 G4, completely stock.
Any ideas?