I was having issues starting connection to internet games, the kellergame Launch.log file was giving me 'unable to open port' messages. I was finally able to track down the problem.

If you are a Window user having trouble connecting to online matches, try the following:

Go to Control Panel->Network Connections.

You should (might) see an entry at the top (above Local Area Connection) called Internet Connection or something like that. Whether or not you see it depends on your current internet/gateway setup.

Open up Properties. You should see a bunch of entries for DemonwarePortMapper. Just delete them all and restart the game.

If you habitually play on a LAN with several other players, all the port entries (307X) tend to get tied up and the game can't find a port to use.