Limit # of free ads

[SkGold]

Dose anybody tried to limit # of free ads with 3.1?
I am using 3.1.10 and trying to implement the code from this thread
I have only one listing package and also using drill mode.
I put the following code in Case 3 - usercheckout.php below $productid=(int)@$_REQUEST['productid'];

PHP Code:

//begin max free ads
$freeID = '1';
if($productid==$freeID)
{
$totalAllowedFree = '1';

$sSQL = sprintf("SELECT oOwnerID FROM ".PREFIX."orders WHERE oOwnerID=%s AND oProductID=%s",
GetSQLValueString($userid, "int"),
GetSQLValueString($freeID, "int"));
$result=$db->query($sSQL);
$numrows = $result->size();

if($numrows > $totalAllowedFree)
{
    //They have too many free ads redirect.
    $location="usercheckout.php";
    $class_tpl->assign('title',"Failure");
    $class_tpl->assign('forward',FALSE);
    $class_tpl->assign('location',$location);
    $class_tpl->assign('msg'," You have exceeded the max free listings. <a href='".$location."'>Place an Ad</a>");
    $class_tpl->assign('body','forward.tpl.php');
    $class_tpl->display('layout.tpl.php');
    exit;
}//end max free ads redirect
}//end max free ads 


But it doesn’t work. It is redirecting to the next step and allow to post more than one listing.

Any help really appreciated.