Well, this one requires Impuse to install, which is known not to work. So, I copied over the game from an installed Boot Camp partition, and tried to run it there.
It has the same problem activating that the main game does. This is an expansion pack, and until Gal Civ II starts working again, this won't work either.
The activation screen comes up, and asks for email/activation code. Unfortunately, the input fields do not seem to function properly. The email field looks like it is letting you type (though you cannot see what you are typing...just blanks appear in a slightly different color, implying a font problem). When you tab to the next field, everything blanks out.
I tried installing Mono, and Impulse still failed, as did the input fields.