jQuery Grid Plugin - jqGrid

I am trying to figure out how to make grouping work, but am not having much success. I have followed all the tutorials etc. but my grids are never grouped - I am sure I am missing something simple.   What are the "requirements" to make it happen?   I have pulled code exactly from the 3.8 remote demo, but it wont work..

In ALL cases data is displayed in a standard flat table listing...

$("#masterList").jqGrid({

url: "sample.json",

datatype: "json",

colNames: ['Inv','Date', 'Client', 'Amount','Tax','Total','Notes'],

colModel:[

{name:'id',index:'id', width:60, editable:true, sorttype:'int',align:"center"},

{name:'invdate',index:'invdate', width:90, sorttype:'date', formatter:'date', datefmt:'d/m/Y',align:"center"},

{name:'name',index:'name', width:100,summary:'count',summaryTpl:'({0}) total'},

{name:'amount',index:'amount', width:80, align:"right", sorttype:'number',formatter:'currency',summaryType:'sum'},

{name:'tax',index:'tax', width:80, align:"right",sorttype:'number',formatter:'currency',summaryType:'sum'},

{name:'total',index:'total', width:80,align:"right",sorttype:'number',formatter:'currency',summaryType:'sum'},

{name:'note',index:'note', width:120, sortable:false,editable:true}

],

rowNum: 10,

forceFit: true,

rowList: [5,10,20,30],

loadonce: true,

height: 'auto',

width: 640,

pager: '#masterPager',

sortname: 'name',

viewrecords: true,

sortorder: "asc",

altRows: true,

altclass: "ui-table-altrow",

grouping: true,

groupingView: {

groupField: ['name'],

groupColumnShow: [true],

groupText: ['<b>{0}</b>'],

groupCollapse: true,

groupOrder: ['asc'],

groupSummary: [true],

showSummaryOnHide: true,

groupDataSorted: true

},

footerrow: true,

userDataOnFooter: true

});