This is a quick guide to the errors you get in multiplayer. (Players)
End of Stream: The Admin shut down the server. With you in it. You just lost everything since your last login. Tough luck.
Timed Out: The server is lagging to hell, and is taking forever to log you in.
Connection Refused: Connect: Server is turned off.
Took to long to log in: YOU are lagging, not the server. Find out why.
Black Screen: Simply means that the client tried to reference something that was not there, causing it to double the item on your computer. Most common when using teleportation.