Face fan page wall post using php SDK

Dear all,

In my website admin page.post a new property.the details are posted in my facebook fan page wall. I am using PHP SDK.
Some times its working fine.
Sometimes redirect to my return url it contains code parameter and stopped
i am using this code

Anyone help me

<?php
require_once 'src/facebook.php';
// configuration
 $appid = '';
 $appsecret = '';
 $pageId = '';
 $msg = $_REQUEST['fbtitle'];
 $title = $_REQUEST['fbtitle'];
 $uri = $_REQUEST['fburl'];
 $desc = $_REQUEST['fbsum'];
 $pic = $_REQUEST['fbimage'];





$facebook = new Facebook(array(
 'appId' => $appid,
 'secret' => $appsecret,
 'cookie' => false,
 ));



$user = $facebook->getUser();

// Contact Facebook and get token
 if ($user) {
 // you're logged in, and we'll get user acces token for posting on the wall
 try {



 $page_info = $facebook->api("/$pageId?fields=access_token");

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

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

$msg="<h2 align='center'>Sucessfully Posted On Facebook Wall</h2>";
 } 
 else 
 {




 $status = 'No access token recieved';
 }

 } 
 catch (FacebookApiException $e) {
 error_log($e);
 $user = null;
 }
 } else 
 {
 // you're not logged in, the application will try to log in to get a access token


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


echo $msg;
 ?>