Someone double check this please?

[iWalletMobile]

Tryin to fun this postback for gWallet and it keeps giving me a sig not ok. Doesnt make any sense to me, the SECRET is perfectly fine. Its asking for everything it should. The sig is verified against the hash which is sent back from gWallet after offer completion on there side and its still giving me problems

<?php
    include "config.php";
 
    //check md5
    $SECRET = 'xxxxxxx';
    $sig = md5($_REQUEST['userId'] . ':' . $_REQUEST['appId'] . ':' . $SECRET);
 
    If($_REQUEST[‘hash’] == $sig) {
        $userdata = GetUserInfo($_REQUEST['userId']);
        $conn = ConnectDB();
        $res = mysql_query('UPDATE users SET points = '.$_REQUEST['amount'].' WHERE userid = '.$_REQUEST['userId'].''. $conn);
        if($res){ print "1"; }
        else{ print "0"; }
    }else{
        print "sig not ok";
    }
	?>