jQuery Grid Plugin - jqGrid

Hi,

I got the following javascript error: “TypeError: Result of expression '$('#grid_customers').jqGrid' [undefined] is not a function.”

I have included the following scripts:
/jquery.jqGrid-3.6/js/i18n/grid.locale-en.js
/jquery.jqGrid-3.6/js/jquery.jqGrid.min.js

Any idea what's wrong?
Thanks,

Renaud 

	$('#grid_customers').jqGrid({
		url:'index.php?output=XMLData&table=customers&xml=1&q=1',
		datatype: 'xml',
		colNames: ['Name', 'Online'],
		colModel: [{name:'name', index:'name'}, {name:'online', index:'online', align:'right'}],
		autowidth: true,
		rowNum: 10,
		rowList: [10,20,30],
		pager: $('#pager_customers'),
		sortname: 'id',
		viewrecords: true,
		sortorder: 'desc',
		caption: 'Customers',
		onSelectRow: function(id){
			customersClick(id);
		}
	}).navGrid('#pager_customers',{edit:false,add:false,del:false});