Problems with header("Location: ")

I'm trying to redirect a user after filling out a form the process SHOULD work like this: User opens page which checks for cookie "usertype" or "usertypesaved" if the cookies are not found, user is redirected to a form to fill out what kind of user he/she is. HTTP_REFERER is added as the value of a hidden form field, so that I can return the user to their original location with usertype set. On submit, the script calls setusertype.php (the code below) ---SNIP---- <?php setcookie("usertype", $userType, 0, "/", ".myserver.com", 0); if ($save=="on" || $save=="On") { $expire = time() + 63072000; setcookie("usertypesaved", $userType, $expire, "/", ".myserver.com", 0); } header("Location: $referer"); ?> --SNIP---- Problem: This works just as it should on mac/IE 5, but not Netscape on mac or any browser on windows. On those browsers, it returns the user to the directory that the php script is in. I have the header("Location: ") function working properly elsewhere, so I'm guessing there's an error in this code (possibly an obvious error I've missed). Any ideas? P.S. I cannot use session variables for this process (at least, not very easily), because usertype must be available to seperate web server, not running php/apache. Dave