Facebook App Postback Script

Hello everyone, I am developing an app for facebook, and I am using SuperRewards for my monetary platform. Well, I have everything set up, but the postback script isn't working, so whenever I test the postback, it doesn't give my admin account the points. Can anyone please help? Below is the script:

<?
include("includes/clsGeneral.php");

//check md5
$SECRET = '***************************';
$sig = md5($_REQUEST['id'] . ':' . $_REQUEST['new'] . ':' . $_REQUEST['uid'] . ':' .
$SECRET);

if($_REQUEST['sig'] == $sig) {
	$userdata = GetUserInfo($_REQUEST['uid']);
	$conn = ConnectDB();
	$res = mysql_query('UPDATE users SET king_author_points + '.$_REQUEST['new'].' WHERE id = '.$_REQUEST['uid'].''. $connection);
	if($res){
		print "1";
	    }else{
		print "0";
	}
    }else{
		print "0";
	}

PHP:

 

It seems right to me, you might want to log the output when the postback script is called!