I've been running FF800 for a few years now and have run into this issue before. The last time it was a simple re-install the drivers fix.
This time that doesn't seem to work.
System:
Mac G5 dual 2.5 (non-intel)
6 Gb ram

I've reset the PRAM/NVRAM as well as the SMC, changed firewire ports and cables and re-installed the drivers.
The issue I'm running into is that the driver seems to not fully install. The Mixer and control panel show up in my applications list but they refuse to open.
Suggestions please.