“The requested address is not valid in its context” – This means you are probably providing an invalid IP address for the remote end. Try running two instances of the example on the local machine and use the loop back address 127.0.0.1
I must admit I find the layout of the project a little unusual for a TCP library. I would be expecting to see something like:
Server server = new TcpServer(connection);
server.dataIn += …etc
This approach would significantly complicate the more advanced features. The approach used by NetworkComms attempts to simplify the connection relationship and the best way to think of everything is a peer to peer connection, rather than a strict client/server relationship.
I can confirm the clientServerExample project (completed downloadable example) does work at my end. Please confirm your usage here to locate the issue.