Well, I've been trying to create a room and every time it just gives me an error saying it's unable to create the room and to try again. It worked once and I did that on accident. Please help me out.

When there are too many servers on line, the main TB server becomes full and you cant create any more servers in multiplayer.

Then all you can do is wait till someone's server disappears, then you can create a new one or you can play in someone's server.