It sounds like the host of the game minidumped.  If you log onto Ironclad Online you can play using Alloy which will in fact migrate the game to someone else.  However, you guys would probably want to restart from the last saved game point.  You could also just restart from the last saved game point over VPN.  The nice thing about Ironclad Online, of course, is that you can play games against other people when your friends aren't available.

Would it be necessary to set up something like port forwarding if you wanted to play over VPN?  I haven't thought about it for a long time, but I think the Sins ports are 6000 and 6112.

you also could use VPN Watcher - it stops all selected applications (including online games, messengers etc) while your vpn connection is broken

can be found here

http://www.ugdsoft.com/products/vpnwatcher