OpenGraph设置自定义PLAY操作

Hi i've with success submitted my PLAY action on openGraph,

Just a question :

To submit sample i use that :

$facebook = new Facebook($config);

$user_id = $facebook->getUser();

if($user_id) {

 try {
    $ret_obj = $facebook->api('/me/mupizfb:play', 'POST',
        array(
            'song' => "http://www.mupiz.com/profil.php?id1=1"
        ));
    echo '<pre>Post ID: ' . $ret_obj['id'] . '</pre>';

  } catch(FacebookApiException $e) {
        error_log($e->getType());
        error_log($e->getMessage());

  }   
} else echo"not connected with FB";

I get no errors.. But nothing was posted on facebook any ideas?

Thanks!