Ah I see 
So this OldWorld Support is coming from OS9 Helper, it's not an Apple thing? I've never used OS9 Helper - it looked from their site as if it doesn't work with the 6100, though quite why it wouldn't I'm not sure, considering that 9.1 is pretty similar and works.
_________________
Main system: custom C2D 2.66GHz tower/4GB RAM/2600XT 512 MB/500GB HD/XP Pro x86+Vista Business x64
Main Mac: Beige G3 minitower (Sonnet G4 500MHz/640 MB DVD/USB/Radeon 32 MB/OS 9.2.2+10.4.11)
So this OldWorld Support is coming from OS9 Helper, it's not an Apple thing? I've never used OS9 Helper - it looked from their site as if it doesn't work with the 6100, though quite why it wouldn't I'm not sure, considering that 9.1 is pretty similar and works._________________
Main system: custom C2D 2.66GHz tower/4GB RAM/2600XT 512 MB/500GB HD/XP Pro x86+Vista Business x64
Main Mac: Beige G3 minitower (Sonnet G4 500MHz/640 MB DVD/USB/Radeon 32 MB/OS 9.2.2+10.4.11)