title: Facebook access_token problem
body: <p>I use a request dialog in my app where the user can send requests to their friends. Once the user sends the request i redirect the app to a page where it posts on the users page. I use the below code to get an access_token:</p>
  
  <pre><code>$ch = curl_init();
  curl_setopt($ch, CURLOPT_URL, 'https://graph.facebook.com/oauth/access_token?client_id='.APP_ID.'&amp;client_secret='.APP_SECRET.'&amp;redirect_uri=http://www.facebook.com/pages/Cosmetics/167231286678063?sk=app_233227910028874&amp;grant_type=client_credentials');
  curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
  curl_setopt($ch, CURLOPT_HTTPAUTH, CURLAUTH_BASIC);
  curl_setopt($ch, CURLOPT_SSL_VERIFYHOST,0);
  curl_setopt($ch, CURLOPT_SSL_VERIFYPEER,0);
  
  $token = curl_exec($ch);
  
  $me = $facebook-&gt;api('/me?'.$token);
  </code></pre>
  
  <p>but when I try to post on the wall it shows this error:</p>
  
  <p>Fatal error: Uncaught OAuthException: Invalid OAuth access token signature. </p>