Going back over what you have written the client error makes sense, if the server cannot start correctly the client has nothing to connect too.
As to why the server is having problems I’m not currently sure why. You are the first person in several thousand to have such a problem. What I would like you to try is replace the following line in the client source:
//Start listening for incoming connections TCPConnection.StartListening(true);
with
//This will force NetworkComms to only listen on adaptors
//with an ip's matching 127.*.*.*
NetworkComms.AllowedIPPrefixes = new string[] { "127" };
//Start listening for incoming connections
TCPConnection.StartListening(true);
Then rebuild, check the “created on” time of the executable to make sure you are executing the new version.
Marc