I have following code and getting "TypeError: jQuery11(...).dataTable is not a function" error. Anyone know why? How I can debug to fix it?

<table id="openCasesTable" class="datagridTable" cellspacing="0">
        <thead>
            <tr class="headers">
                <th>ID</th>
                <th>First Name</th>
                <th>Last Name</th>
                <th>Group Name</th>
                <th>Requested Date</th>
                <th>Status</th>
                <th>History</th>
                <th>Remove</th>
            </tr>
        </thead>
        <tbody>
        </tbody>
    </table>
<script type="text/javascript" src="<c:url value="/assets/scripts/lib/jquery/jquery-1.11.1.js"/>"></script>
<script type="text/javascript">
var jQuery11 = $.noConflict(true);
</script>
<script type="text/javascript" src="//cdn.datatables.net/1.10.2/js/jquery.dataTables.min.js"></script>

<script language="javascript">
jQuery11(document).ready(function () {
    alert($.fn.jquery); //OK display old jquery version
    alert(jQuery11.fn.jquery); //OK display jquery 11
    jQuery11('#openCasesTable').dataTable();
});