about xpcommexception

Hi,
I tried to execute the following example given in the javaxpcom page

     Mozilla moz = Mozilla.getInstance();
     nsIServiceManager serviceManager = moz.getServiceManager();
     nsIAppStartup appStartup =
(nsIAppStartup)serviceManager.getServiceByContractID("@mozilla.org/
toolkit/app-startup;1", nsIAppStartup.NS_IAPPSTARTUP_IID);
     nsIWindowCreator windowCreator =
(nsIWindowCreator)appStartup.queryInterface(nsIWindowCreator.NS_IWINDOWCREATOR_IID);

     nsIWindowWatcher windowWatcher =
(nsIWindowWatcher)serviceManager.getServiceByContractID("@mozilla.org/
embedcomp/window-watcher;1", nsIWindowWatcher.NS_IWINDOWWATCHER_IID);
     windowWatcher.setWindowCreator(windowCreator);

     nsIDOMWindow win = windowWatcher.openWindow(null, "chrome://your-
app/content/window.xul", "mywindow", "chrome,resizable,centerscreen",
null);
     windowWatcher.setActiveWindow(win);
      appStartup.run();

but it showing error
Exception in thread "main" org.mozilla.xpcom.XPCOMException: Attempt
to use unitialized XPCOM object  (0x80004003)
        at org.mozilla.xpcom.Mozilla.getServiceManager(Mozilla.java:
715)

i am using Redhat enterprise linux v4....