the script gives error "The parameter app_id is required" in facebook login even when passed in the code

Question

i have developed a website in which i want to incorporate "login with facebook" button. i have coded the necessary part and also made the facebook application for it..in my code i have even passed the app id and secret key. Even after doing so when i press the button to login via facebook it gives me an error "The parameter app_id is required" . this is my login script

    <?php 
            include 'fbaccess.php'
            if(empty($user))
            {
            ?>
            <form name="fblogin" action="<?php echo $loginUrl;?>">
            <input type="submit" name="fbsubmit" value="Login with Facebook"/>
            </form>
            <?php                   
            } 
            else {
                echo $user_info;
            }
            ?>

and this is my fbaccess.php code

    <?php
     $app_id        = APP_ID;
     $app_secret    = APP_SECRET;
     $site_url  = "www.jajabora.com/index.php";

     include_once "src/facebook.php";

     //creating the object of facebook from the API
     $facebook = new Facebook(array(
 'appId'        => $app_id,
 'secret'   => $app_secret,
  ));

      //getting the user id to check whether the user is logged in or not
       $user = $facebook->getUser();

      //if user is not authenticated api/me will throw an exception, hence we will know                he isnt logged in after logging out
      /*checks if the user is logged in or not*/if($user){
      // Single query method 
  try{
    // Proceed knowing you have a logged in user who's authenticated.
    $user_profile = $facebook->api('/me');
   }/*if exception the user has logged out after logging in hence not authenticated*/
  catch(FacebookApiException $e){
    error_log($e);
    $user = NULL;
  }
      // Single query method ends 
      }
       if($user){
  // Get logout URL
  $logoutUrl = $facebook->getLogoutUrl();
      }else{
  // Get login URL
  $loginUrl = $facebook->getLoginUrl(array(
    'scope' => 'publish_stream, user_birthday,user_location,email,first_name,last_name,gender',
    ));
       }
      if($user){
  // Proceed knowing you have a logged in user who has a valid session.

      //========= Batch requests over the Facebook Graph API using the PHP-SDK ========
  // Save your method calls into an array
  $queries = array(
    array('method' => 'GET', 'relative_url' => '/'.$user)/*,
    array('method' => 'GET', 'relative_url' => '/'.$user.'/home?limit=50'),
    array('method' => 'GET', 'relative_url' => '/'.$user.'/friends'),
    array('method' => 'GET', 'relative_url' => '/'.$user.'/photos?limit=6'),*/
    );

   // POST your queries to the batch endpoint on the graph.
   try{
    $batchResponse = $facebook->api('?batch='.json_encode($queries), 'POST');
     }catch(Exception $o){
    error_log($o);
      }

    //Return values are indexed in order of the original array, content is in   ['body'] as a JSON
   //string. Decode for use as a PHP array.
    $user_info      = json_decode($batchResponse[0]['body'], TRUE);
    $feed           = json_decode($batchResponse[1]['body'], TRUE);
    /*$friends_list     = json_decode($batchResponse[2]['body'], TRUE);
    $photos         = json_decode($batchResponse[3]['body'], TRUE);*/
        //========= Batch requests over the Facebook Graph API using the PHP-SDK ends =====

       try {
   $publishStream = $facebook->api("/$user/feed", 'post', array(
    'message'       => 'Check out jajabora.com',
    'link'          => 'http://jajabora.com'/*,
    'picture'       => 'http://25labs.com/images/25-labs-160-160.jpg'*/,
    'name'          => 'Jajabora',
    'caption'       => 'jajabora.com',
    'description'       => 'A carpooling website. highly recommended to  save fuel and cost of travel',
    ));
           }catch(FacebookApiException $e){
         error_log($e);
               }
                }
              ?>

Please guide me. i am a newbie in facebook login coding

Solution

I suspect that problem might be hiding here:

<form name="fblogin" action="<?php echo $loginUrl;?>">
        <input type="submit" name="fbsubmit" value="Login with Facebook"/>
</form>

You are sending get request to the generated link, why? User is supposed to follow that link and give your application permissions, try something like this instead of the form:

<a href="<?php echo $loginUrl?>">Login with Facebook </a>

In order to redirect user to certain page, add redirect_uri to getLoginUrl:

$loginUrl = $facebook->getLoginUrl(array(
'scope' => 'publish_stream, user_birthday,user_location,email,first_name,last_name,gender',
redirect_uri => PAGE_URL
));

Make sure that this page belongs to the domain your set up in app settings.