DOMNotSupportedException in com.sun.java.browser.dom.* classes

Question

I'd like to enable an applet to modify the DOM in a browser window directly (ie. by using org.w3c.dom.* stuff). I'm using the latest 1.5.
I'm using a small class that I've pasted below to attempt to facilitate this. It evidently works in MSIE, where I receive the "Got document" message indicating a non-null value for 'page', but in Mozilla or Netscape, I get the following exception thrown:
netscape.javascript.JSException
     at netscape.javascript.JSObject.getWindow(Unknown Source)
     at sun.plugin.dom.DOMServiceProvider.getDocument(Unknown Source)
     at sun.plugin.dom.DOMAccessor.getDocument(Unknown Source)
     at econ.ClientLink.run(ClientLink.java:35)
     at sun.plugin.dom.DOMService.invokeLater(Unknown Source)
     at econ.ClientLink.start(ClientLink.java:25)
     at sun.applet.AppletPanel.run(Unknown Source)
     at java.lang.Thread.run(Unknown Source)
com.sun.java.browser.dom.DOMUnsupportedException
     at sun.plugin.dom.DOMServiceProvider.getDocument(Unknown Source)
     at sun.plugin.dom.DOMAccessor.getDocument(Unknown Source)
     at econ.ClientLink.run(ClientLink.java:35)
     at sun.plugin.dom.DOMService.invokeLater(Unknown Source)
     at econ.ClientLink.start(ClientLink.java:25)
     at sun.applet.AppletPanel.run(Unknown Source)
     at java.lang.Thread.run(Unknown Source)
Got document: null
Is this just simply only supported for MSIE? This seems highly unlikely.
I suspect it might have something to do with permissions in Mozilla, as these lines also appear in the log:
liveconnect: the url of the applet is http://word and the permission is = false
liveconnect: JavaScript: calling Java system code
liveconnect: JavaScript: default security policy = http://word
I haven't yet found anyone who could explain them. I'd like to try playing with permissions, buy I don't know how to do so. Any suggestions?
--- code follows ---
import javax.swing.*;
import java.applet.*;
import org.w3c.dom.*;
import com.sun.java.browser.dom.*;
public class ClientLink extends JApplet implements DOMAction {
DOMService service;
Document page;
public void start() {
try {
service = DOMService.getService(this);
System.out.println("Got service.");
service.invokeLater(this);
catch (Exception e) {
e.printStackTrace();
public Object run(DOMAccessor doma) {
System.out.println("Entry successful.");
try {
page = doma.getDocument(this);
System.out.println("Got document: "+page);
catch (Exception e) {
e.printStackTrace();
System.out.println("Error: "+e.toString());
return null;
}

Answer 1

A couple of things I've found with DOMService and/or LiveConnect and the more recent java and browser releases :
1) You probably need to edit your java.policy file to grant permissions since the security in Java is now managed independently from the browser
2) You need to remember to have mayscript="true" in your applet tag
3) JSObject's dont work unless you've called JSObject.getWindow(...) first.
4) Many legitimate java exceptions will appear misleadingly as security exceptions