System profiler reported something like "unable to display firewire devices". So you may be on to something. It was a brand new Rocketfish cable from Best Buy. i am not on Lion, i'm on "Snow Leopard" (isn't that an endangered species?).
when i unplug the firewire cable, the system profiler says "firewire bus: up to 800 mbps"- as normal.
BTW, FCP will not let me select "view> all frames" from the View menu, external video. I guess it has to recognize the FW cable/bus first?
i will see if i can exchange this cable for another and see what happens.