VS 2010 commands works on 2008... not on 2010 why?

Kinda new to .Net... These commands work on 2008 but did not work on 2010 when i imported them...



ClientSocket = New Socket(AddressFamily.InterNetwork, _
SocketType.Stream, ProtocolType.Tcp)
Dim address As IPAddress = _
System.Net.Dns.GetHostEntry(txtAddress.Text).AddressList(0)
Dim endpoint As New IPEndPoint(address, CInt(txtPort.Text))
ClientSocket.BeginConnect(endpoint, AddressOf Connected, Nothing)

any ideas?