VB Script locks up Rhino5

CAn anyone tell me why the following script locks up Rhino?  I enter it into the Grasshopper Script Editor and hit [OK] and it locks up:

''your code goes here…
    Dim server As Net.Sockets.TcpListener    server = Nothing    Try      ' Set the TcpListener on port 6001.      Dim port As Int32 = 6001      Dim localAddr As Net.IPAddress = Net.IPAddress.Parse("127.0.0.1")
      server = New Net.Sockets.TcpListener(localAddr, port)
      ' Start listening for client requests.      server.Start()
      ' Buffer for reading data      Dim bytes(1024) As Byte      Dim data As String = Nothing
      ' Enter the listening loop.      While True        Console.Write("Waiting for a connection... ")
        ' Perform a blocking call to accept requests.        ' You could also user server.AcceptSocket() here.        Dim client As Net.Sockets.TcpClient = server.AcceptTcpClient()        Console.WriteLine("Connected!")
        data = Nothing
        ' Get a stream object for reading and writing        Dim stream As Net.Sockets.NetworkStream = client.GetStream()
        Dim i As Int32
        ' Loop to receive all the data sent by the client.        i = stream.Read(bytes, 0, bytes.Length)        While (i <> 0)          ' Translate data bytes to a ASCII string.          data = System.Text.Encoding.ASCII.GetString(bytes, 0, i)          Console.WriteLine("Received: {0}", data)
          ' Process the data sent by the client.          data = data.ToUpper()          Dim msg As Byte() = System.Text.Encoding.ASCII.GetBytes(data)
          ' Send back a response.          stream.Write(msg, 0, msg.Length)          Console.WriteLine("Sent: {0}", data)
          i = stream.Read(bytes, 0, bytes.Length)
        End While
        ' Shutdown and end connection        client.Close()      End While    Catch e As Net.Sockets.SocketException      Console.WriteLine("SocketException: {0}", e)    Finally      server.Stop()    End Try
    Console.WriteLine(ControlChars.Cr + "Hit enter to continue....")    Console.Read()