could not load main init file?

[prokras]

Hi, I downloaded the Amnesia: a Dark Descent demo from Steam but when I tried to run it on Mac, it gave me a message: could not load the main init file. I ran the demo on Windows 7 on the same machine and it ran just fine so spec isn't the issue but I'd prefer it to run on the Mac instead.

I have mid 2010, 13" MBP and I've tried reinstalling and launching the game directly from the installation folder but still no luck. Probably worth noting that I'd tried to download the game for the first time days before but the download was corrupted (steam said it was done but it wasn't and I couldn't run it, it was a different error from this one) so I deleted it. and this time, it finished downloading but I got this error. I've checked the said file and it wasn't broken and I've deleted the file then put it back, still got the error message.

please help!