Currently I have DoubeCommand set to recognize the Enter key on my Macbook as an Option key. This worked just fine on a Powerbook I was running recently, but when I moved over to the Macbook, it refused to recognize a specific keystroke: RightCommand-RightOption-RightArrow. The Enter-as-Option key works just fine otherwise, including:
RightCommand-RightOption-LeftArrow
LeftCommand-RightOption-RightArrow
Command-Option and an Arrow key, incidentally, is how one navigates using tabs in Camino.
I had a friend download DoubleCommand and Camino onto his Macbook, and he replicated the error. It seems that the entire keystroke is just ignored by the system, which means it can't be assigned as a keyboard shortcut in the Keyboard and Mouse preference pane, either.
Please feel free to email jason /at/ doombot /dot/ com if this turns out to be helpful.
I'm having the exact same problem with my Macbook Pro. Please email me if there's anything I can do to help.