I also tested it on Windows XP 32bit, fully updated, and it worked fine. You will need to make sure that you have UPnP installed in Windows, SSDP and UPnP services enabled, UPnP enabled on the router, and so on. If it does not work, this usually indicates that something is not configured correctly. You may want to try the PortForward tool, which is what I use to ensure that UPnP is configured and working correctly.