Facebook API - fql_query, Invalid Session

I am trying to request Facebook using the PHP library and what I have read does not need to have a session key, or rather it should not require one for my case, but my code below gives me the following error: "The session key is invalid or is no longer valid. "

http://wiki.developers.facebook.com/index.php/Fql.query "For example, querying a user table is like calling users.getInfo without a session key - you can only query a few fields."

$fb = new Facebook(FACEBOOK_KEY, FACEBOOK_SECRET);

$query = "SELECT uid,
    name,
    sex,
    pic_square,
    profile_url
    FROM user WHERE name = 'some name' OR username = 'some name'";

$result = $fb->api_client->fql_query($query);

      

        
        
        
      

    

Any ideas?

/Thanks