It appears that some time between 2010 and 2019, Sourceforge stopped allowing
PHP pages to be accessed.  It lies and gives HTTP response code 404 (page not
found).

It does work somehow when the PHP page is referenced from another page on
Sourceforge.  E.g. you can get 'download.php' if you click on the link to it
on 'index.html'.  I don't know how this works; simply using the Referer header
field doesn't seem likely, because the requester could just lie.

So this directory is no longer useful as a demonstration XML-RPC server
and as a demonstration of simple PHP XML-RPC.

The file sample.php.tar contains the sample.php file that Sourceforge won't
let you see.

Alexey Loginov got this code to work on another web server in May 2019, but
had to remove ampersands in front of the $this->errno and $this->errstr
arguments to fsockopen().  We suspect that change is necessary because of some
change in PHP, and have made that change here.