Register Globals = OFF not passing variable

Hey Folks,
I can use some help here.  I am changing some scripts around so they
work with (register) globals off.  I am trying to pass variables in a
function  and it does not seem to be passing.  The script work fine
with globals turned on.  I would really like to have them work with RG
turned off.  Any help would be appreciated.  Here is a short example:

<PHP
function display_private_results($user_id, $area, $username)
{
if ($_POST['postback_private_results'])
{
include "include/db.php";
$query = "SELECT routes.*, users.* FROM users, routes WHERE
area='$area' AND username='$username' ";
and so on...

Much Thanks,
Craig