I started having some strange issues with FCP Studio 1, using multiple FW drives daisy-chained on an iMac G5 2.1 GHz. Eventually, FCP would not open.
After a few hours and several Tech Support folks, I ended up with a Final Cut Pro Product Specialist who said weirdnesses will eventually occur in FCP with daisey-chained drives. He stresses that only one device (no hubs) should be plugged into each of the two FW ports on the iMac.
I changed my ways and have had no further problems (1 year+).
Lee HIlliard
hcg1000@earthlink.net