With the last fix, I added a folder issue Steam couldn't handle.
The funny part is, that I tried the functionality after the upload and everything worked fine. Steam is still a mystery to me.
So - now the game works again.

It might be, that you have to reinstall the game again.
But the magical science upgrades and the statistics aren't affected by the reinstall.

I'm very very sorry for acting that late (didn't see that there's a problem!). I was very busy the last weeks and on vacation as well.

Have fun while playing the game now!
Greetings,
IsaVII