[Cap'n Steve]

Ok, that's pretty weird. The one on my site works fine for me, but the one on your site doesn't. What kind of internet connection do you have and where do you host your site? Do you use a proxy or anything else unusual?

The code is right since it prints it for me, there must be something to do with your connection that's blocking the referer from being sent and also something with your version of PHP that's not setting the appropriate variable.