jQuery Grid Plugin - jqGrid

Hi,

Im a newbie. Following the documentation I tried to use jQuery Grid without connecting to the DB. I send the data using JSON and It seems to be ok at the Body Layer except that at the middle apears a label with an undefined text inside it and the Navigation Layer doesn't seems to work. My servlet code is:

 protected void processRequest(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        response.setContentType("application/json;charset=UTF-8");
        PrintWriter out = response.getWriter();
        try {
            out.print("{"
                    + ""total": "2",\n"
                    + ""page": "1",\n"
                    + ""records": "12",\n"
                    + ""datos" : [\n"
                    + "{"id" : "1", "cell" : ["1", "Josefina Villegas", "27"]},\n"
                    + "{"id" : "2", "cell" : ["2", "Mario Miki", "30"]},\n"
                    + "{"id" : "3", "cell" : ["3", "Eloisa Avila", "28"]},\n"
                    + "{"id" : "4", "cell" : ["4", "Erandi Urban", "26"]},\n"
                    + "{"id" : "5", "cell" : ["5", "Ivan Ortega", "26"]},\n"
                    + "{"id" : "6", "cell" : ["6", "Rodrigo Avila", "30"]},\n"
                    + "{"id" : "7", "cell" : ["7", "Carlos Miki", "28"]},\n"
                    + "{"id" : "8", "cell" : ["8", "Roberto Miki", "30"]},\n"
                    + "{"id" : "9", "cell" : ["9", "Rogelio Navarrete", "28"]},\n"
                    + "{"id" : "10", "cell" : ["10", "Sergio Prado", "26"]},\n"
                    + "{"id" : "11", "cell" : ["11", "Cristina Amparan", "26"]},\n"
                    + "{"id" : "12", "cell" : ["12", "Norma Barreiro", "30"]},\n"
                    + "]\n"
                    + "}");
        } finally {
            out.close();
        }
    }

The idea is to use the Navigator Layer to see the last two "rows", but the navigation layer doesn't appear. My js code is this:

 <script type="text/javascript"> jQuery(document).ready(function(){
    jQuery("#list").jqGrid({ url:'respuestaJSON', datatype: 'json', mtype: 'GET',
        jsonReader : {root:"datos",page: "page",total: "total",records: "records"},
        colNames:['id','Nombre', 'Edad'],
        colModel :[ {name:'id', index:'id', width:55},
            {name:'Nombre', index:'Nombre', width:150, align:'right'},
            {name:'Edad', index:'Edad', width:80, align:'right'}],
        pager: jQuery('#paginador'), rowNum:15, rowList:[10,20,30],sortname: 'id',
        sortorder: "desc",
        viewrecords: true,
        caption: 'Primer prueba'
    });
});
</script>

Any advice is welcome. Thanks in advance.