If you are getting a permission denied message in Mozilla's javascript console, close Mozilla and add the following pref to your prefs.js:
user_pref("signed.applets.codebase_principal_support", true);
When you re-run this page, it will ask you to grant permissions. You should probably check
"remember this decision" and click "Ok". Now, you will see the script work in Mozilla.
The alternative is to sign the script, but I haven't found this to be working very well in Mozilla (Mozilla's signtool utility doesn't seem to work properly) and signed scripts have been implemented differently between Netscape4 and Mozilla/Netscape6.
If you get a javascipt error saying "permission denied" when running this script, go into Tools/Internet Options..., then click the "Security" tab. Click the "Custom Level..." button. Now scroll down to "Miscellaneous" and look for "Access data sources across domains". Click the "Enable" or "Prompt" radio button (I suggest Prompt to be a bit safer). Click "Ok" twice and reload this page. You should see a popup prompting you as to whether to access information that isn't under this page's control. Click "Yes" and the script will be run.
Again, an alternative is to sign the script, but there seem to be even fewer resources detailing that with IE than with Netscape. And, IE and Netscape's script signing is incompatible anyway. Hopefully there is a middle ground so that we can create some compatibility layer.