Very weird.

But still thank you. I just found an old save of my map where I did not add the second brute yet. Guess I just have to try this one out.
I also deleted the stuff you were talking about, but it still crashed so it seems it had nothing to do with that.
Where exactly do I have to put the MapsFolder = "maps/" in the cfg file? And after the / I guess I have to add the name of the map right? xD (Sorry, like I said I'm really new to that.. I really hope I don't bother you with such little things.. ^^")
Edit: I've now loaded the older map where I have not placed the second brute and it seems to work perfectly fine. Guess I just have to go on with that, although I really don't get it.

Anyway, thank you SO much for your help. Without you I guess I would have gone crazy!