Hi, am trying to use a multicast socket in an application but I constantly get this exception; java.net.SocketException: error setting options. I have failed to find its cause and how to solve it. Pliz help (what could be causing it, and how can i solve it?

i have noticed that the problem only comes up when i try to run it offline.
How can i successfully test a multicast prog when offline. am using windows xp.