On 19.02.2010 14:07, JeffWinder wrote: > > hi, > > I have Monodevelop on a Mac and it uses System.dll version 2.0.0.0. > > I think I need 3.5.0.0 because I want to use the System.Net.EndPoint class. System.Net.EndPoint is as old as .NET 1.0. I believe you're simply not referencing System.dll from your project. Robert