I have the following jqGrid (using 3.4b2):   

$("#tableContainer").jqGrid({
        jsonReader:{
          root: "rows",
          page: "page",
          total: "total",
          records: "orderlines",
          repeatitems: false,
          id: "0"
        },
        url:'/Cart.action?_eventName=fetchOrderlines&id=' + orderId,
        datatype : 'json',
        colNames:['Title'],
        colModel:[
            {name: 'title.name', index: 'title.name', width:215, align: 'left', jsonmap: 'title.name'}
        ]
    }).navGrid('#pagerdt',{edit:false,add:false,del:false});

The JSON returned from my url is:

{
    "total": 1,
    "orderlines": [
        {
            "available": false,
            "branchDistribId": 12001390,
            "branches": {

            },
            "callNumber": null,
            "cartCheck": "|Test Cart Symbol",
            "class": "com.mwt.beans.OrderLineExpanded",
            "filled": null,
            "fundId": 8700560,
            "id": 12244008,
            "internalNotes": null,
            "lineItem": null,
            "marcBrief": false,
            "marcOclc": false,
            "marcVolumes": false,
            "mwtPrice": 0.0,
            "notes": null,
            "oclcCost": "$0.00",
            "orderId": 0,
            "otherCartId": 0,
            "previouslyPurchased": false,
            "price": "$39.99",
            "processPrice": "$0.00",
            "product": {
                "available": false,
                "bugHtml": null,
                "bw": false,
                "cardboard": false,
                "cartName": null,
                "catalogName": null,
                "cc": true,
                "circ": "N",
                "clam": false,
                "class": "com.mwt.beans.Product",
                "copyprotect": false,
                "customerPrice": 0.0,
                "dewey": null,
                "displayAfter": null,
                "doubleside": false,
                "dubbed": false,
                "ep": false,
                "format": null,
                "id": 0,
                "img": null,
                "isbn": "9781419848858",
                "isbnOld": null,
                "masterSku": null,
                "media": "HD DVD",
                "miscInfo": "HD DVD & Standard DVD, widescreen",
                "mwtPrice": 0.0,
                "oclc": "141251838",
                "oclcMarcAvailable": false,
                "oclcStatus": null,
                "pieces": 0,
                "preorderDate": null,
                "previousPurchases": 0,
                "priceKey": null,
                "pubSku": null,
                "releaseDate": null,
                "replacements": 0,
                "retailPrice": 0.0,
                "sdh": false,
                "set": false,
                "setId": 0,
                "sku": "WAR113764H",
                "spanish": false,
                "streetDate": 1185858000000,
                "subtitled": false,
                "titleId": 0,
                "upc": "085391137641",
                "used": 0,
                "volume": null,
                "wide": true
            },
            "productId": 11356959,
            "qty": 18,
            "rating": null,
            "replaceQuantities": false,
            "retailPrice": "$39.99",
            "shopperId": 670357,
            "showDetails": false,
            "source": null,
            "spineLabel": null,
            "status": null,
            "statusText": null,
            "subtotal": "$719.82",
            "title": {
                "abridged": false,
                "actors": null,
                "anscr": null,
                "artistFirstName": null,
                "artistLastName": null,
                "artistName": null,
                "boxOfficeGross": 211.0,
                "class": "com.mwt.beans.Title",
                "cleanTitleId": null,
                "comments": 0,
                "country": null,
                "description": null,
                "directors": null,
                "explicitTitleId": null,
                "genre": "Drama",
                "id": 0,
                "img": "war113764h.gif",
                "kind": "VIDEO",
                "language": null,
                "masterSku": null,
                "maxArtistAchievement": null,
                "minutes": 0,
                "muzeId": null,
                "name": "300",
                "notes": null,
                "position": 0,
                "producers": null,
                "products": [

                ],
                "productsInCirc": [

                ],
                "rating": null,
                "ratingDescription": null,
                "releaseYear": null,
                "replacement": false,
                "salesRankAll": 89025,
                "salesRankRecent": 80307,
                "seriesId": 0,
                "studio": null,
                "suggestedAudience": null,
                "year": 0
            }
        }
    ],
    "page": 1,
    "records": 66
}