Há algum problema em usar InternalFrames em um applet????

E ae pessoal. É o seguinte... tenho uma classe que fica responsável por lançar InternalFrames. Ela funciona como aplicativo perfeitamente! Mas ao chamá-la em um applet os InternalFrames não aparecem! Segue os códigos... se puderem me ajudar! :)

//esse é o método dentro da classe DesktopFrame que lança os internal frames:public void lancarMapa(){ JInternalFrame frame = new JInternalFrame( "Internal Frame", true, true, true, true ); MyJPanel panel = new MyJPanel(); // create new panel frame.add( panel, BorderLayout.CENTER ); // add panel frame.pack(); // set internal frame to size of contents theDesktop.add( frame ); // attach internal frame frame.setVisible( true ); // show internal frame frame.setSize(500,380); frame.setResizable( false ); frame.setMaximizable( false );}
import java.awt.BorderLayout;import java.awt.Container;import java.awt.event.ActionEvent;import java.awt.event.ActionListener;import javax.swing.JApplet;import javax.swing.JButton;import javax.swing.JPanel;public class appletJF extends JApplet{	private Container container;	private JButton botao = new JButton();	private JPanel panelPrincipal = new JPanel(); private DesktopFrame desktopFrame = new DesktopFrame(); /** * Construtor appletJF; * */	public appletJF()	{ //setLayout( new BorderLayout() ); //botao.setBounds(250, 10, 80, 40); botao.setText("adicionar"); botao.addActionListener( new ActionListener() // anonymous inner class { //display new internal window public void actionPerformed( ActionEvent event ) { desktopFrame.lancarMapa(); } // end method actionPerformed } // end anonymous inner class ); panelPrincipal.add( botao ); container = getContentPane(); container.setLayout( new BorderLayout() ); container.add( panelPrincipal, BorderLayout.EAST );	}	}Vlw pessoal! 

Os erros que aparecem:

Exception in thread "AWT-EventQueue-2" java.security.AccessControlException: access denied (java.net.SocketPermission 200.131.219.53:8080 connect,resolve) at java.security.AccessControlContext.checkPermission(Unknown Source) at java.security.AccessController.checkPermission(Unknown Source) at java.lang.SecurityManager.checkPermission(Unknown Source) at java.lang.SecurityManager.checkConnect(Unknown Source) at sun.awt.SunToolkit.createImage(Unknown Source) at MyJPanel.atualizaMapa(DesktopFrame.java:142) at MyJPanel.<init>(DesktopFrame.java:114) at DesktopFrame.lancarMapa(DesktopFrame.java:80) at appletJF$1.actionPerformed(appletJF.java:37) at javax.swing.AbstractButton.fireActionPerformed(Unknown Source) at javax.swing.AbstractButton$Handler.actionPerformed(Unknown Source) at javax.swing.DefaultButtonModel.fireActionPerformed(Unknown Source) at javax.swing.DefaultButtonModel.setPressed(Unknown Source) at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(Unknown Source) at java.awt.Component.processMouseEvent(Unknown Source) at javax.swing.JComponent.processMouseEvent(Unknown Source) at java.awt.Component.processEvent(Unknown Source) at java.awt.Container.processEvent(Unknown Source) at java.awt.Component.dispatchEventImpl(Unknown Source) at java.awt.Container.dispatchEventImpl(Unknown Source) at java.awt.Component.dispatchEvent(Unknown Source) at java.awt.LightweightDispatcher.retargetMouseEvent(Unknown Source) at java.awt.LightweightDispatcher.processMouseEvent(Unknown Source) at java.awt.LightweightDispatcher.dispatchEvent(Unknown Source) at java.awt.Container.dispatchEventImpl(Unknown Source) at java.awt.Component.dispatchEvent(Unknown Source) at java.awt.EventQueue.dispatchEvent(Unknown Source) at java.awt.EventDispatchThread.pumpOneEventForHierarchy(Unknown Source) at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source) at java.awt.EventDispatchThread.pumpEvents(Unknown Source) at java.awt.EventDispatchThread.pumpEvents(Unknown Source) at java.awt.EventDispatchThread.run(Unknown Source)