Every time that i try to log in the multiplayer that error Jump: "an error has occured please check your network connectivity"
It start from when I changed my modem maybe that is the problem
Can somebody help me?
Thanks

You said this is since your change of the modem, right?
Take a look at your "modem-rules" an at your firewall. Maybe your PC or the game hasn't the full right to use internet.

Can you tell me more about this I can't find the problem?
thanks

Check here: http://www.gamesas.com/forums/viewtopic.php?f=40&t=11027