Error when attempting to access Referer

When attempting to access this link, http://jigsaw.w3.org/css-validator/check/referer,  I get a message once the page loads which reads,

"Some Headers, mandatory for this resource, are missing.

 *   Referer"
This is the only thing that show up on the page that loads. I thought you might like to know about this.
Also referrer has 2 Rs: referrer.
Thanks
Sam

Received on Wednesday, 30 October 2013 08:28:51 UTC