I had to forward 29060-29099 UDP (AND TCP) before I could play & host JA without problems. So try that...
And disable ZoneAlarm if you use it.
As to the master server thing, edit your cfg file and add the ones from this thread:
http://www.lucasforums.com/showthrea...hreadid=143023
About switching gametypes mid game:
http://www.lucasforums.com/showthrea...hreadid=143036