code: protected void sendError( String errText, HttpServletRequest request, HttpServletResponse response )
          throws IOException
      {
          InternalUtils.sendError( "PageFlow_Custom_Error", null, request, response,
                                   new Object[]{ getDisplayName(), errText } );
      }
docs: Send a Page Flow error to the browser.
  
  @param errText the error message to display.
  @param response the current HttpServletResponse.