jQuery Grid Plugin - jqGrid

The following code is not deleting the selected entries. What am I doing wrong, please.

require_once '../includes/jquery/jq-config.php';
// include the jqGrid Class
require_once "../includes/jquery/php/jqGrid.php";
// include the PDO driver class
require_once "../includes/jquery/php/jqGridPdo.php";
// Connection to the server
$conn = new PDO(DB_DSN,DB_USER,DB_PASSWORD);
// Tell the db that we use utf-8
$conn->query("SET NAMES utf8");

// Create the jqGrid instance
$grid = new jqGridRender($conn);
// Write the SQL Query
$grid->SelectCommand = "select lead_id,lastname,firstname,phone,concat_ws(', ',streetno,street,suburb,town) as addr,ddate from ".$filterfile;

// Set the table to where you add the data
$grid->table = $filterfile;

$grid->setPrimaryKeyId('lead_id');

// set the ouput format to json
$grid->dataType = 'json';
// Let the grid create the model
$grid->setColModel();
// Set the url from where we obtain the data
$grid->setUrl('getaLeads.php');
// Set grid caption using the option caption
$grid->setGridOptions(array(
    "caption"=>"Leads",
    "rowNum"=>12,
    "sortname"=>"lastname",
    "rowList"=>array(12,30,50),
    "multiselect"=>true,
    "height"=>270,
    "width"=>1000
    ));

// Change some property of the field(s)
$grid->setColProperty("lead_id", array("label"=>"ID", "width"=>20, "hidden"=>true));
$grid->setColProperty("lastname", array("label"=>"Last Name", "width"=>190));
$grid->setColProperty("firstname", array("label"=>"First Name", "width"=>100));
$grid->setColProperty("phone", array("label"=>"Phone", "width"=>80));
$grid->setColProperty("addr", array("label"=>"Address", "width"=>250));
$grid->setColProperty("ddate", array("label"=>"Date", "width"=>100, "formatter"=>"date"));

$dblclick = <<<ONDOUBLECLICK
function(rowid) {
    var rowdata = $("#aleadlist").getRowData(rowid);
    var leadid = rowdata.lead_id;
    viewlead(leadid);
}
ONDOUBLECLICK;
$grid->setGridEvent('ondblClickRow',$dblclick);

// enable form editing
$grid->navigator = true;
$grid->setNavOptions('navigator',array('add'=>false,'edit'=>false));
$grid->setNavOptions('del',array("jqModal"=>false));

// Run the script
$grid->renderGrid('#aleadlist','#aleadpager',true, null, null, true,true);