Mac Upgrading Problem

[Buzzard]

Just purchased and downloaded the Demon War expansion pack from your Soldak site. The installation process appeared to work normally, and the expansion folder is inside the "Expansions" folder as (presumably) it should be.

When attempting to start the game, the start-up fails with the following Critical Error message: "Couldn't find base MusicBase referenced in MusicDemonWalker"

I repeated the installation process, with no change in the result.