Error connecting to the Server

I’ve been trying to get my nephew setup so we can play on-line. They can browse to www.vassalengine.org and ‘see’ the server/rooms there. When they open Vassal, open a module, select ‘Look for on-line game’, they get the following error stack:

java.net.UnknownHostException: www.vassalengine.org
at java.net.PlainSocketImpl.connect(Unknown Source)
at java.net.Socket.connect(Unknown Source)
at java.net.Socket.connect(Unknown Source)
at sun.net.NetworkClient.doConnect(Unknown Source)
at sun.net.www.http.HttpClient.openServer(Unknown Source)
at sun.net.www.http.HttpClient.openServer(Unknown Source)
at sun.net.www.http.HttpClient.(Unknown Source)
at sun.net.www.http.HttpClient.New(Unknown Source)
at sun.net.www.http.HttpClient.New(Unknown Source)
at sun.net.www.protocol.http.HttpURLConnection.getNewHttpClient(Unknown Source)
at sun.net.www.protocol.http.HttpURLConnection.plainConnect(Unknown Source)
at sun.net.www.protocol.http.HttpURLConnection.connect(Unknown Source)
at sun.net.www.protocol.http.HttpURLConnection.getInputStream(Unknown Source)
at VASSAL.chat.HttpRequestWrapper.doGet(HttpRequestWrapper.java:90)
at VASSAL.chat.HttpRequestWrapper.doGet(HttpRequestWrapper.java:47)
at VASSAL.chat.DynamicClient.getServerConfig(DynamicClient.java:65)
at VASSAL.chat.DynamicClient.buildDelegate(DynamicClient.java:55)
at VASSAL.chat.DynamicClient$1.doInBackground(DynamicClient.java:85)
at VASSAL.chat.DynamicClient$1.doInBackground(DynamicClient.java:82)
at org.jdesktop.swingworker.SwingWorker$1.call(Unknown Source)
at java.util.concurrent.FutureTask$Sync.innerRun(Unknown Source)
at java.util.concurrent.FutureTask.run(Unknown Source)
at org.jdesktop.swingworker.SwingWorker.run(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)

Can anyone help?

I am also having the exact same issue with my Vassal.