System.NullReferenceException: Object reference not set to an instance of an object.
   at ScruffyDuck.Flightsim.Scenery.SceneryObject.AirportRecord.TaxiwayPath.Code(FileType fileType)
   at ScruffyDuck.Flightsim.Scenery.SceneryObject.AirportRecord.TaxiPathCollection.Code(FileType fileType)
   at ScruffyDuck.Flightsim.Scenery.SceneryObject.Airport.Code(FileType fileType)
   at ScruffyDuck.Flightsim.Scenery.SceneryFile.SceneryFile.Code(FileType fileType)
   at ScruffyDuck.AirportDesignEditor.MainForm.GenerateBglSourceXml(String path)
   at ScruffyDuck.AirportDesignEditor.MainForm.SaveFS20ProjectData()
   at ScruffyDuck.AirportDesignEditor.MainForm.OnSaveAdeMenuItemClick(Object sender, EventArgs e)
   at System.Windows.Forms.ToolStripItem.RaiseEvent(Object key, EventArgs e)
   at System.Windows.Forms.ToolStripMenuItem.OnClick(EventArgs e)
   at System.Windows.Forms.ToolStripItem.HandleClick(EventArgs e)
   at System.Windows.Forms.ToolStripItem.HandleMouseUp(MouseEventArgs e)
   at System.Windows.Forms.ToolStripItem.FireEventInteractive(EventArgs e, ToolStripItemEventType met)
   at System.Windows.Forms.ToolStripItem.FireEvent(EventArgs e, ToolStripItemEventType met)
   at System.Windows.Forms.ToolStrip.OnMouseUp(MouseEventArgs mea)
   at System.Windows.Forms.ToolStripDropDown.OnMouseUp(MouseEventArgs mea)
   at System.Windows.Forms.Control.WmMouseUp(Message& m, MouseButtons button, Int32 clicks)
   at System.Windows.Forms.Control.WndProc(Message& m)
   at System.Windows.Forms.ScrollableControl.WndProc(Message& m)
   at System.Windows.Forms.ToolStrip.WndProc(Message& m)
   at System.Windows.Forms.ToolStripDropDown.WndProc(Message& m)
   at System.Windows.Forms.Control.ControlNativeWindow.OnMessage(Message& m)
   at System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m)
   at System.Windows.Forms.NativeWindow.Callback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)