I am not able to display grid data using json data return by ajaxcall. Here is my json response:

{"Total":27,"Page":1,"Records":1337,
"Rows":[
{"ID":2769,"NickName":"?test.asp?id=88&a=test","Type":1,"Scoring"
:0,"PageURL":"http:\/\/xxx.com?test.asp?id=88&a=test","Grouping":0,"Content":"Default","Index"
:1},
{"ID":2736,"NickName":"15 TIPS FOR ACCELERATING","Type":1,"Scoring":20,"PageURL":"http:\/\/www.yyy
.com\/InfoCenter\/landing_15tipstoacceleratesales.asp?","Grouping":0,"Content":"Default","Index":2},
...
 ]
}

I am setting grid like:
$("#activityScoreGrid").jqGrid({
                url: "/scoring/getNickNames",
                dataTtpe:"json",
                height: '100%',
                width: '100%',
                colNames: ['NickName','Url'],
                colModel: [
                    {sortable:false, resizable:false, width:500,   name:"NickName",   index:"NickName"},
                    {sortable:false,  resizable:false, width:500, name:"PageURL", index:"PageURL"}
                ],
                loadonce:   true,
                gridview:   true,
                jsonReader: {
                    root: "Rows",
                    page: "Page",
                    total: "Total",
                    records: "Records",
                    repeatitems: false,
                    cell: "cell",
                    id: "ID"
                }
            });

Can someone please take a look let me know what could be wrong with the above?

Thanks for the help.