I'm using sessions and a logout.php page when the person wants to log out. Here's the code:

PHP Code:
  session_start();
  require_once(
'globalsettings.inc.php');
  require_once(
'functions.inc.php');
  
logout();
    
  
// reroute to calendar home page
  
redirect2URL("index.php");
  exit; 
The logout function simply does this:
PHP Code:
    function logout() {
        unset(
$_SESSION["AUTH_USERID"]);
        unset(
$_SESSION["AUTH_SPONSORID"]);
        unset(
$_SESSION["AUTH_SPONSORNAME"]);
        unset(
$_SESSION["AUTH_ADMIN"]);
    } 
This is not working in IE or FF though, and I never get logged out. What is going wrong?