Facebook PHP SDK，发布到另一个用户墙是什么错？

Question

您好这是我的测试代码，以便发布到Facebook墙。如果SOME_USER是我的工作，如果它是另一个用户，它不会！有人可以解释什么是错的吗？谢谢!!

我的应用程序处于沙箱模式，但我也尝试过，没有任何改变！

    <?php
     require_once 'src/facebook.php';

     $msg = 'Some message would go here.';
     $title = 'Some title would go here';
     $uri = 'http://test.com';
     $desc = 'Some detailed message.';
     $action_name = 'Action Link in the Footer of the Post';
     $action_link = 'http://www.test.com';
     $scope = "publish_stream,publish_actions";

    $app_id = "xxx";
    $app_secret = "xxxx";
    $facebook = new Facebook(array(
            'appId' => $app_id,
            'secret' => $app_secret,
            'cookie' => true
    ));


    $user = $facebook->getUser();

     if ($user) {

         try {
            $accessToken = $facebook->getAccessToken();

            if (!empty( $accessToken )) {
                     $attachment = array(
                         'access_token' => $accessToken,
                         'message' => $msg,
                         'name' => $title,
                         'link' => $uri,
                         'description' => $desc,
                         'picture'=>$pic,
                         'actions' => json_encode(array('name' => $action_name,'link' => $action_link,'scope' => $scope))
                      );

$status = $facebook->api("/SOME_USER/feed", "post", $attachment);

             } 
         } catch (FacebookApiException $e) {

                    $user = null;

         }
     }else {

         header("Location:{$facebook->getLoginUrl(array('scope' => 'publish_stream,publish_actions'))}");
     }