You post error dialog boxes in response to a failure condition that the application cannot resolve.
Error dialog boxes have the following characteristics:
The application name is displayed in their title bar.
An error symbol is displayed on the left side of the dialog box.
The action area contains only a Dismiss button.
They are modal.
For example:
mainWindow = getAFXApp().getAFXMainWindow() showAFXErrorDialog(mainWindow, 'An invalid value was supplied.')