Помогите пжлс разобраться, почему ошибка!


public void actionPerformed(ActionEvent e) {
new ProgressFrame(MyFrame,"Wait ...",new Runnable() {public void run() {
try {
//Code
}catch(Exception e){
System.out.Println("Error?!!!-1");
}
}
});
}
--------------------------------------------------------------

public class ProgressFrame {
JDialog progressDialog;
Thread thread;
public ProgressFrame(JFrame parent, String title, final Runnable task) {
progressDialog = new JDialog(parent, title, true);
final JProgressBar progressBar = new JProgressBar();
progressBar.setIndeterminate(true);
JPanel panel = new JPanel();
//...
panel.add(progressBar);
progressDialog.getContentPane().add(panel);

progressDialog.pack();
progressDialog.setSize(300,progressDialog.getHeight());
progressDialog.setResizable(false);

thread = new Thread() {
public void run() {
try {
task.run();
progressDialog.dispose();
}
catch (Exception e) {
System.out.Println("Error?!!!-2");
}
}
};
thread.start();
try{
progressDialog.show();
}catch (Exception e){
System.out.Println("Error?!!!-3");
}
}

}

Exception occurred during event dispatching:
java.lang.NullPointerException
at javax.swing.text.html.BlockView.paint(BlockView.java:263)
at javax.swing.plaf.basic.BasicTextUI$RootView.paint(BasicTextUI.java:1319)
at javax.swing.plaf.basic.BasicTextUI.paintSafely(BasicTextUI.java:636)
at javax.swing.plaf.basic.BasicTextUI.paint(BasicTextUI.java:770)
at javax.swing.plaf.basic.BasicTextUI.update(BasicTextUI.java:749)
at javax.swing.JComponent.paintComponent(JComponent.java:541)
at javax.swing.JComponent.paint(JComponent.java:808)
at javax.swing.JComponent.paintWithOffscreenBuffer(JComponent.java:4787)
at javax.swing.JComponent.paintDoubleBuffered(JComponent.java:4740)
at javax.swing.JComponent._paintImmediately(JComponent.java:4685)
at javax.swing.JComponent.paintImmediately(JComponent.java:4488)
at javax.swing.RepaintManager.paintDirtyRegions(RepaintManager.java:410)
at javax.swing.SystemEventQueueUtilities$ComponentWorkRequest.run(SystemEventQueueUtilities.java:117)
at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:178)
at java.awt.EventQueue.dispatchEvent(EventQueue.java:454)
at java.awt.EventDispatchThread.pumpOneEventForHierarchy(EventDispatchThread.java:201)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:151)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:141)
at java.awt.Dialog$1.run(Dialog.java:540)
at java.awt.Dialog.show(Dialog.java:561)
at rdfmapper.utils.ProgressFrame.<init>(ProgressFrame.java:76) //public class ProgressFrame {....
at rdfmapper.panelrdf.PanelRDF.actionPerformed(PanelRDF.java:110) //public void actionPerformed(ActionEvent e) {...
at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:1786)
at javax.swing.AbstractButton$ForwardActionEvents.actionPerformed(AbstractButton.java:1839)
at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:420)
at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:258)
at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:245)
at java.awt.Component.processMouseEvent(Component.java:5100)
at java.awt.Component.processEvent(Component.java:4897)
at java.awt.Container.processEvent(Container.java:1569)
at java.awt.Component.dispatchEventImpl(Component.java:3615)
at java.awt.Container.dispatchEventImpl(Container.java:1627)
at java.awt.Component.dispatchEvent(Component.java:3477)
at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:3483)
at java.awt.LightweightDispatcher.processMouseEvent(Container.java:3198)
at java.awt.LightweightDispatcher.dispatchEvent(Container.java:3128)
at java.awt.Container.dispatchEventImpl(Container.java:1613)
at java.awt.Window.dispatchEventImpl(Window.java:1606)
at java.awt.Component.dispatchEvent(Component.java:3477)
at java.awt.EventQueue.dispatchEvent(EventQueue.java:456)
at java.awt.EventDispatchThread.pumpOneEventForHierarchy(EventDispatchThread.java:201)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:151)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:145)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:137)
at java.awt.EventDispatchThread.run(EventDispatchThread.java:100)

Ошибка выпадает один раз из 3-5. Причем все работает как надо!