HTTP Authentication not getting unset

Hey all, New problem. I really hope there's something simple to do to fix it. Check out this scenario and tell me if there's a step that I'm missing. Inside my common footer on my site the very first call is to an include called UserAuth.inc.php. UserAuth.inc.php checks $REQUEST_URI to see if the present directory or URL is protected or not. If it is protected then it checks to see if $PHP_AUTH_USER is set. If it is then it runs through the usual HTTP Authentication. If it fails it goes to a failure page, if it succeeds then it logs the user in. Now I can surf around on the site and that same authentication will continue to be used for the rest of the site where ever another protected directory or file is found (as to be expected). Now to logout I have a page called logout.php. If you go to this page (which also includes the same footer) there is another action that takes place. If the $REQUEST_URI contains logout.php then I print the same "401" header that I print for authentication and unset $PHP_AUTH_USER, $PHP_AUTH_PW and $AUTH_USER. $AUTH_USER is the user authentication object in my class file UserAuth.class.php. I'm just unsetting this so that no code will still have record of the old authentication object to do anything with. Now if I try to read the $PHP_AUTH_USER or $PHP_AUTH_PW variables anyplace on the site they don't exist, until I go back to one of the protected pages. Then they miraculously re-appear and are readily available once again without requiring the user to log back in. If you've got any ideas, suggestions, guesses or references, please reply. I've run out of ideas. I can also provide the code that I'm using if you think it might just be a problem with my logic. I don't think this is the case as I shouldn't be able to read any variable that has been unset, but like I said, I'm running out of ideas. System: RedHat 6.1-6 i686 Kernel 2.2.13 Server: Apache 1.3.12 PHP: 4.0.3pl1 Thanks, Toby