It's probably a power problem.
I've had a similar problem.
When I used my Aptus22 on the AFD/II with a 10mtr firewire cable to a repeater (without power) and the original leaf cable it all worked flawless.
When I switched to the RZ the orange light would come on, the back would spin up but no connection and no connection on my macbook pro, on my macpro it did work.
When I powered my repeater it did work.
I changed the 10mtr firewire cable for a 5 mtrs and now both cameras work without any problem.
You're response that it's all the fault of the Leaf is not correct.
When a camera works on another system it's always something else that is going wrong, it's very simple when a camera works it works.
When it doesn't work under another OS or on another computer you have to look for the problem somewhere else, in this probably power.
In this case the problem is I THINK a power problem, if you want to be sure buy for a few dollars a power firewire hub/repeater and try if it works than with the other camera.
I think it will.
I know there have been serious problems tethering digital backs to Macbook pro's 17" in the past.
I know my MBP will only last 45 minutes before giving me "stripes" in my images, that's why on location we run from the applejuicze batteries which gives me app 4 hours of working time with the back connected.
Frank, can you provide a link where I can read/buy about these batteries and how to connect them to Macbook Pro 17"?
Regarding power, lets look at these simple schemas:
Apple MBP -> OWC Adapter 800 -> Leaf Cable 400-400 -> Leaf Aptus 65 -> Camera A
Apple MBP -> OWC Adapter 800 -> Leaf Cable 400-400 -> Leaf Aptus 65 -> Camera B
Macbook Pro provides power to Aptus via the same Adapter 800 and Leaf FireWire cable 400-400 (4.5 meters, not very long).
This part of the electrical schema doesn't change.
The only difference is the Camera A and Camera B, which are not connected to the FireWire power.
So, I can theoretically accept that it could be somehow relative to the FireWire power, however I don't understand how.