发布到多个Facebook朋友墙（在我的情况下为20）

I'm doing a facebook app and it was working good till yesterday. I did was let user's choose 20 of their friends and wrote a simple script to post to their wall from a loop like this:

foreach($selectedids as $selectedid) {
    $invitation = new Invitations();
    $invitation->circle_id = $circle->id;
    $invitation->status = 0;
    $invitation->follower_id = $selectedid;
    if ($invitation->create()) {
        $id = $invitation->id;
        // Now Send the Invitations on Facebook
        $facebook->api($selectedid.'/feed', 'post', array(
            'picture' => '',
            'message' => $name."something",
            'name' => $config['app_title'],
            'link' => $config['redirect_uri']."?invitation=".$id,
            'caption' => '',
            'description' => '',
            'actions' => array(array('name' => 'Get Search',
                                     'link' => 'http://www.google.com'))
        ));
    }
}

Till yesterday everything was fine but when now multiple user's use this at once the script would stop after a post to about 7-8 friend and give an error that it couldn't complete task. Is there a better way to post to multiple peoples in facebook? What shall I do, would make this perform better? Any suggestions would be much appreciated.

Checking log an exception: 'error 201 user not visible' was found.

Thanks in advance.

The error was due the user not being able to post to his friends wall which I solved by doing a check before posting by running a fql to check 'can_post' to user's friends wall. Solution can be viewed at.

Check if a facebook user can post in his friends wall or not

How about puting the api call into a variable and checking the variable.?

$result = $facebook->api($selectedid.'/feed', 'post', array(
            'picture' => '',
            'message' => $name."something",
            'name' => $config['app_title'],
            'link' => $config['redirect_uri']."?invitation=".$id,
            'caption' => '',
            'description' => '',
            'actions' => array(array('name' => 'Get Search',
                                     'link' => 'http://www.google.com'))
        ));

Because if it is successfull, it will send you back the id of the post.