Can you show me where you tested it? It works fine on all sites that I have checked. And that is the correct code to use.
I did find that some forums have a problem with it, not because of the code, but because the portal page is a redirect from the index.htm or index.html page which holds the
PR. if displayed on the portal page it would show the portals
PR, and not the index's
PR. The script as with the google toolbar will show the
PR of the page you are viewing, not the main domain's
PR.