DatePicker Error in IE8

[Cyndie]

I'm receiving the following error when a date is either typed in or selected in a DatePicker in IE8 (doesn't happen in IE9)

Microsoft JScript runtime error: Object doesn't support property or method 'substr'
The error is happening on line 1346 of kendo.web.js

The DatePicker is in a pop-up editor:
The data is queried via a web service with a JSON response.

I am using a custom parser for the date returned from the service

I'm not sure why I'm receiving this error.

function customParser(data) {

    if (data != null) {

        var str = data.toString();

        if (str.indexOf("Date") >= 0)

            return new Date(parseInt(data.substr(6)));

    }

    else

        return data;

<!-- datepicker editor for field: "ManufactureDate" -->

        <input type="text"

            name="ManufactureDate"

            data-type="date"

            data-bind="value:ManufactureDate"

            data-role="datepicker" />



[Cyndie]

I figured out the issue.  I was using the parser for display purposes, but it was not needed for the datepicker.