i am trying to add this script to my iframe app on facebook but it seems not to work:
$signed_request = $facebook->getSignedRequest(); $like_status =
I had similar problem a while ago - the solution was to specify full url for tab or/and canvas page to receive signed request.
Example: use http://myapp.com/myapp/index.php, isntead of http://myapp.com/myapp/