It doesn't say anything after "Referrer" in either Firefox 1.5.0.1 or IE 6.0.2900

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.

Weird...my site is hosted in the USA but I am in Japan. I am not using a proxy.
I have cable/dsl (i think). Its built into my apartment building, so I am not exactly sure what I have.

My PHP (4.4.0) is in safe mode...could that be the issue?

The safe mode might explain why it doesn't work on your site, but it doesn't explain why you can't see it on my site. You might want to ask your host why the $_ENV['HTTP_REFERER'] variable doesn't get set properly.

Actually, I can see it on your site...I take it back. I think I must have clicked through from my topic notification email.

Well that makes a little bit more sense. I've never heard of a server setup that blocks the referer from being used, but I'll investigate further.