If your browser properly passes the HTTP_REFERER string, it should be displayed in the box below:
(none)
If the box above says "(none)", then your browser is not passing HTTP_REFERER.
The box should read "http://karmak.org/2004/reftest/"; if it does not, the browser may be passing an incorrect HTTP_REFERER (make sure you start from the Start Page).
If your browser is not passing the HTTP_REFERER, or is passing the wrong HTTP_REFERER, see this page.