My wife and I have been getting the "An unknown error has occurred" message, where it kicks you out of the game and back to the login screen. Now of course they have changed the message slightly, but it still does not give an error number or any meaningful information about the error.
We finally got a response back from customer support, and their suggestion was to turn on Port Forwarding on the router for a couple of specific port ranges. Of course this was another canned response and made no reference to the fact that our support ticket indicated there were multiple PCs involved.
My impression of port forwarding is that the router would then forward all traffic for specific ports to one specific IP address on our network. And if it does that, then won't that prevent the other PC from connecting at all? Or can you forward the same ports to multiple PCs?