----An error occured----
Referencia a objeto no establecida como instancia de un objeto.

----Stacktrace----
   en FoolEditor.DBLoader.Tables_FillList(ComboEditorTool cbo)
   en FoolEditor.MainWindow.rbtDBImport_Click(Object sender, RoutedEventArgs e)
   en System.Windows.EventRoute.InvokeHandlersImpl(Object source, RoutedEventArgs args, Boolean reRaised)
   en System.Windows.UIElement.RaiseEventImpl(DependencyObject sender, RoutedEventArgs args)
   en Infragistics.Windows.Ribbon.ButtonTool.ButtonToolProxy.OnMenuItemClick(ButtonTool tool)
   en Infragistics.Windows.Ribbon.Internal.RibbonToolProxy`1.OnMenuItemClick(FrameworkElement tool)
   en Infragistics.Windows.Ribbon.ToolMenuItem.OnClick()
   en System.Windows.Controls.MenuItem.ClickItem(Boolean userInitiated)
   en System.Windows.Controls.MenuItem.HandleMouseUp(MouseButtonEventArgs e)
   en System.Windows.Controls.MenuItem.OnMouseLeftButtonUp(MouseButtonEventArgs e)
   en System.Windows.RoutedEventArgs.InvokeHandler(Delegate handler, Object target)
   en System.Windows.EventRoute.InvokeHandlersImpl(Object source, RoutedEventArgs args, Boolean reRaised)
   en System.Windows.UIElement.ReRaiseEventAs(DependencyObject sender, RoutedEventArgs args, RoutedEvent newEvent)
   en System.Windows.UIElement.OnMouseUpThunk(Object sender, MouseButtonEventArgs e)
   en System.Windows.RoutedEventArgs.InvokeHandler(Delegate handler, Object target)
   en System.Windows.EventRoute.InvokeHandlersImpl(Object source, RoutedEventArgs args, Boolean reRaised)
   en System.Windows.UIElement.RaiseEventImpl(DependencyObject sender, RoutedEventArgs args)
   en System.Windows.UIElement.RaiseEvent(RoutedEventArgs args, Boolean trusted)
   en System.Windows.Input.InputManager.ProcessStagingArea()
   en System.Windows.Input.InputManager.ProcessInput(InputEventArgs input)
   en System.Windows.Input.InputProviderSite.ReportInput(InputReport inputReport)
   en System.Windows.Interop.HwndMouseInputProvider.ReportInput(IntPtr hwnd, InputMode mode, Int32 timestamp, RawMouseActions actions, Int32 x, Int32 y, Int32 wheel)
   en System.Windows.Interop.HwndMouseInputProvider.FilterMessage(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam, Boolean& handled)
   en System.Windows.Interop.HwndSource.InputFilterMessage(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam, Boolean& handled)
   en MS.Win32.HwndWrapper.WndProc(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam, Boolean& handled)
   en MS.Win32.HwndSubclass.DispatcherCallbackOperation(Object o)
   en System.Windows.Threading.ExceptionWrapper.InternalRealCall(Delegate callback, Object args, Boolean isSingleParameter)
   en System.Windows.Threading.ExceptionWrapper.TryCatchWhen(Object source, Delegate callback, Object args, Boolean isSingleParameter, Delegate catchHandler)