The XAO tutorials rely on the XAO library to demonstrate functionality.
Unfortunately, this ISP (SourceForge), don't provide a service which is up to the minimum requirement for XAO. XAO requires PHP version 4.3.3 and the enablement of the DOMXML extension (which is bundled as standard with default PHP distributions). After some months, SF have not responded to my request for more information on the status of their PHP server and it's ellegability for an upgrade. More recently I have followed this up with another support request.
You can access the tutorials by downloading the full XAO library distribution and installing it on your server.
If you're really desparate, you can access them from Conny Brunnkvist's website for as long as Connie is feeling generous enough to host it.