I keep getting errors when I try to host a game. If one of the players' computers crashed during the game, all of the players may have to reboot in order to clear the problem. If multiple Speed Demon games are happening on the same network, you may have to name them differently in the Host dialog. The host computer is probably not hosting a game at that time. Also be sure you have the right IP number or address for the host computer.
Network games are out of sync.
Your network connection is too slow. Demon interpolates players' positions between network packets, so if you're running into this problem, you've really got a slow connection on your hands. Another possibility is that you or another player is spending a lot of time typing in chat messages. Limit your chatting to before the gameplay starts, and it may help. I don't get a score report for everybody who played in a network game.