header() vs HTTP_REFERER (Netscape 6)

I had now found the problem. The website that have been in use for a while work pretty well with IE and Netscape Navigator. Until NS6 came, that's when the website start having some problem. The website use the login page and any web pages after logging are controlled by the security check. Security check is made of scripts that check to be sure there is no direct access attempt and it also use the cache expiration, etc. So, I noticed when I use the HTTP_REFERER on every web pages as part of the security check, it work pretty well. However, when I use the php code, "header();" and automatically go to the next web page, the HTTP_REFERER can't recieve data from the last page that use the php code, "header();". It only affected NS6, it doesn't affected IE and Netscape Navigator. Why is that? What is the work-around to this problem? Thanks, Scott