thats because the matchserver uses port 7777 udp for get the peer list
if u want host 2 matchservers in same PC u must:
- get open 2 matchservers (so easy)
- change the udp and tcp ports in server (easy also)
- change the UDP port at client for each server, this is the hardest part because the client try to connect to port 7777 always (noone did it yet)
hope it helps u