System.Net.Sockets.SocketException was unhandled
  Message="A socket operation was attempted to an unreachable host"
  Source="System"
  ErrorCode=10065
  NativeErrorCode=10065
  StackTrace:
       at System.Net.Sockets.Socket.setMulticastOption(SocketOptionName optionName, MulticastOption MR)
       at System.Net.Sockets.Socket.SetSocketOption(SocketOptionLevel optionLevel, SocketOptionName optionName, Object optionValue)
       at LanChat1.LanChat..ctor() in E:\Users\Staulkor\Documents\Visual Studio 2005\Projects\LanChat1\LanChat1\LanChat.cs:line 42
       at LanChat1.Program.Main() in E:\Users\Staulkor\Documents\Visual Studio 2005\Projects\LanChat1\LanChat1\Program.cs:line 22
       at System.AppDomain.nExecuteAssembly(Assembly assembly, String[] args)
       at System.AppDomain.ExecuteAssembly(String assemblyFile, Evidence assemblySecurity, String[] args)
       at Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssembly()
       at System.Threading.ThreadHelper.ThreadStart_Context(Object state)
       at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
       at System.Threading.ThreadHelper.ThreadStart()