jQuery Grid Plugin - jqGrid

HI

I am using JQuery grid with Asp.net . I am having a problem I get this message when ever my grid gets load.

$.jgrid.default is null or not an object.

I am having "JsonResult" result returned from the controller I am also wrinting the code here.

$('#list').jqGrid({

              url: '../../Home/getgriddata',

               datatype:'json',

               mytype:'get',

              colNames:['Id','Name','Description'],

               colModel:[

                       {name:'id',index:'id',width:55,resizable:true},

                       {name:'name',index:'name',width:90,resizable:true},

                       {name:'description',index:'description',width:120,resizable:true}],

               pager:$('#pager'),

               rownum:10,

               rowlist:[10,20,30],

               sortname:'id',

               sortorder:'desc',

               viewrecords:true,

               multiselect: true, 

               multikey: "ctrlkey",

               //imgpath:'../../img/basic/images',

               caption: 'mvc the hell'

          });

If ang one knows the soultion please let me know.