Regarding "Client not responding": It is known to happen when a player is in "Receiving..." state (black screen) for a long time after joining the game - depending on his connection. This is related to the BE integration code and will be fixed in the next version.
You shouldn't be kicked for that while playing though - except if a client loses connection due to a game crash of course.
Please also try the new BE Server version (you get it via auto-update). Some improvements have been made regarding this and other matters.