Requires user session error while using FQL in facebook-Collection of common programming errors

I am making a fb app and this is what I need to do:

I get the page id of a business page and I need to get the admin_id of the page. I am using the following code and I get the error message which I have copied at the end.

Can anyone kindly help me ? Thanks.

include_once 'facebook.php';

$facebook = new Facebook($api_key, $secret);

//$page_ids == page_id of a business/fan page  

$query="SELECT uid from page_admin where page_id =".$page_ids.";";

$admins =$facebook->api_client->fql_query($query);

foreach ($admins as $jerry) {
  echo $jerry['uid']."
"; }

error message:

Fatal error: Uncaught exception 'FacebookRestClientException' with message 'Requires user session' in /var/www/seanpeace/data/www/ Stack trace: #0 /var/www/seanpeace/data/www/ FacebookRestClient->call_method('facebook.fql.qu...', Array) #1 /var/www/seanpeace/data/www/ FacebookRestClient->fql_query('SELECT uid from...') #2 {main} thrown in /var/www/seanpeace/data/www/ on line 3112

Originally posted 2013-11-19 13:18:15.