ADN auth issue

adn-auth.php

<?php
require_once('keys.php');  // Where my constants are defined
require_once('AppDotNet.php');

$clientId     = ADN_CLIENT_ID;
$clientSecret = ADN_CLIENT_SECRET;
$redirectUri  = ADN_REDIRECT_URI;

# User has authorized:
if (isset($_GET['code']) && !empty($_GET['code'])) {
  $app = new AppDotNet($clientId, $clientSecret);

  // get the token returned by App.net
  // (this also sets the token)
  $token = $app->getAccessToken($redirectUri);

  // get info about the user
  $user = $app->getUser();

  echo var_dump($user);
  echo var_dump($token);
}

# User has not yet authorized:
else {
  // construct the AppDotNet object
  $app = new AppDotNet($clientId, $clientSecret);
  $scope = array('stream','email','write_post','follow','messages');

  // create an authentication Url
  $url = $app->getAuthUrl($redirectUri,$scope);
  echo '<p><a href="' . $url . '">Please log in</a></p>';
}

?>