Erro em um JMenu

private JMenuItem getAboutMenuItem() {
		if (aboutMenuItem == null) {
			aboutMenuItem = new JMenuItem();
			aboutMenuItem.setText("Ajuda");
			aboutMenuItem.addActionListener(new ActionListener() {
				public void actionPerformed(ActionEvent e) {
					JDialog aboutDialog = getAboutDialog();
					aboutDialog.pack();
					Point loc = getJFrame().getLocation();
					loc.translate(20, 20);
					aboutDialog.setLocation(loc);
					aboutDialog.setVisible(true);
				}
			});
		}
		return aboutMenuItem;
	}

	
	protected JDialog getAboutDialog() {
		return null;
	}