i have found this to be a better way to restore session data while keeping your current session.
function decode_session($session_string){
$current_session = session_encode();
foreach ($_SESSION as $key => $value){
unset($_SESSION[$key]);
}
session_decode($session_string);
$restored_session = $_SESSION;
foreach ($_SESSION as $key => $value){
unset($_SESSION[$key]);
}
session_decode($current_session);
return $restored_session;
}
enjoy