Did you get it to work?
I'm installing the MAC version myself. Here's how I did it.
The base mod itself loads. Here is how you do it: Installed the mod PieAncientEuropeV as written in the instructions. Don't install the patch. Load the mod through BTS/advanced/load mod. While it starts loading the mod the mac usually switches from BTS to steam when you are on the desktop. Switch back to BTS. Then 2 xml error pop up. Press enter twice and the mod will load.
@PiE: I cant get the patches to load though. If I try to install them and load the game ignoring the xml error popups the game crashes giving me the GFC error alert. I'm trying to play the 40civ map. If I only change the files in PieExtra and put the WBsave file in the private maps I can start the mod I can't load the scenario because the WBsave can't be read. Any idea what I could do? Is the 40civ scenario simply too large?