When I join a game it loads perfectly fine and the server starts. There is an option to join a team by pressing "m". So I press it and nothing happens. There is a small picture on the screen, it looks like three moniters linked to a red cross in the centre. What does this mean and how can i start the game!

Sounds like you have a firewall preventing connection.

Make sure all ports Crysis Wars uses are forwarded to be allowed from your firewall, and join servers that have the lowest ping possible. Also make sure your anti-virus is not scanning during gameplay or that could be blocking access as well.