If your computer is behind a router, Rival Ball Tournament may not allow you to host any games. We use some tricks to work around the problem, but these tricks don't work with some routers.
If you're having trouble hosting a game, the solution is called port forwarding. For those who are technically minded, you need to forward a UDP port in the 24200-24216 range.
If you're not technically minded, no worries! The nice people at www.portforward.com have added a tutorial for Rival Ball Tournament to their site, so you can get easy-to-follow instructions by heading over to this page. All you need to do is select the model of your router, and follow the instructions!