I can't establish Fire Wire 800 communication between FCP 7.0.3 and Canon HV 10 which I use as a deck. It happens only When I want to use the new late 2010 Mac Pro. There is no problem with FW communication and Log and Capture initialization with MP 2006 and MBP 2008. USB communication between Canon Vixia and new MP works fine.
What drives are you using, how everything's connected, what settings are on the media, what settings you're using in Final Cut, and what version of the OS are you are using.
Are you connected to the rear FireWire port? Have you tested your MP 2006 and MBP 2008 with the FW800 cable you are using?
Not to hijack the thread, but I've seen questions lately about which FW ports people are using. Is there a demonstrable difference between the front and rear FW ports on a Mac Pro? Does it depend on what vintage your MP might be?