JQuery AJAX callback troughs an error
[WebMethod]
        public FileInfo[] GetFileInfo(int Id)
        {
            Proxies.ServiceRef.ServiceClient c = new Proxies.ServiceRef.ServiceClient();
            return c.GetFileInfo(Id).ToArray();
        }

$.ajax({
                url: url,
                data: jsonData,
                type: "POST",
                contentType: _I.contentType,
                timeout: _I.timeout,
                dataType: "serviceproxy",  // custom type to avoid double parse
                dataFilter: function (jsonString, type) {
                    if (type == "serviceproxy") {
                        // Use json library so we can fix up dates
                        var res = JSON.parseWithDate(jsonString);
                        if (res && res.hasOwnProperty("d"))
                            res = res.d;
                        return res;
                    }
                    return jsonString;
                },
                ***success: function (result) {
                    if (callback)
                        callback(result);***
                }
                   error: function(xhr, error).......

{"d":[{"__type":"Proxies.AFARServiceRef.AssignmentInfo","ExtensionData":{},"AssignDate":"/Date(1317748587667)/","AssignFileName":null,"ClaimId":"PA026195","ClaimantName":"Rachel Weiss","FirstContactDate":"/Date(1302678000000)/","FirstContactTime":{"Ticks":433800000000,"Days":0,"Hours":12,"Milliseconds":0,"Minutes":3,"Seconds":0,"TotalDays":0.50208333333333333,"TotalHours":12.049999999999999,"TotalMilliseconds":43380000,"TotalMinutes":723,"TotalSeconds":43380},"Id":5257,"InspectionDate":"/Date(1302246000000)/","StatusId":1,"SubmittedCount":5,"UploadedCount":9}]}

success: function (result) {
  if (callback){
    callback(result);
  }
},
error: function(xhr, error)