Exception occurred: Argument cannot be null.
Parameter name: path2

System.ArgumentNullException: Argument cannot be null.
Parameter name: path2
  at System.IO.Path.Combine (System.String path1, System.String path2) [0x00000] 
  at VersionControl.AddIn.CheckoutCommand.Run () [0x00000] 
  at MonoDevelop.Components.Commands.CommandHandler.Run (System.Object dataItem) [0x00000] 
  at MonoDevelop.Components.Commands.ActionCommand.DispatchCommand (System.Object dataItem) [0x00000] 
  at MonoDevelop.Components.Commands.CommandManager.DispatchCommand (System.Object commandId, System.Object dataItem, System.Object initialTarget) [0x00000]