I have the problem that SS2 freezes when I want to host a game. Any Idea on that topic? (I used the HOTU-Version og the Game)

Do you have any firewalls running? A firewall asking for permission to allow SS2 hosting might hang the game, and since hte game hogs the screen the firewall won't be able to draw that allow-deny dialog. Also, a firewall blocking SS2 from accessing any network might send SS2 into an infinite loop when hosting (the game will try to search for a valid host IP, but since it's denied from every network it will never succeed) causing SS2 to hog your screen and creating a crash again.

If you have any firewall running, you might wanna check how SS2 behaves if you shut them down and then launch SS2 and try hosting. (Just turning off might not cut it.)