i have a problem a problem with crysis 2 on multiplayer:it sometimes in rooms it give me out from the multiplayer mode and it says the connection of the opponent failed.and it remove my lasts progress...pls help me

Hi,
One Reason could be that you cannot "connect" with the Player who hosts this session. So if the current Hostplayer leaves you get d/c from the Server.
Before you join a server, select it in the server Browser with one click and press Info on Button of the screen. If you can see (Details of the Server) Players you should can connect and Play. What if you join an empty server and wait for 3 players more? Ever tried?

this happens only sometimes and the other players continue playing in that server

yes. because they can connect with each other...If you look for the server details (info) and you see player you should play there