[Vince]

There are two possibilities:

1. The server is off-line or unreachable (e.g. due to firewall rules)
2. Client-server version mismatch

Neither of which have anything to do with a gamemode. If your server is 0.3z and you client is 0.3.7 you simply won't be able to connect. Also it does not bode well to insult the people that are trying to help you.