Windows doesn't ask me for a serial, but Mac does

[xoagray]

Hi,

I bought this game off Desura a long time ago, recently posted about trying to get it to run on my Mac, (seems the issue was fixed, though I was never told about it, not very nice). I noticed that the files are now available on Desura as a DMG which is great and the install went perfectly, but now it's telling me I need a serial to run the game.

Desura never gave me a serial. Where do I find / can I get a serial for this game?

Thanks.
X