Problem with Sortable

Problem with Sortable

I have a problem with Sortable.
I'v copied from demo to my site the strings below, but the item, what I move, doesn't move. But all items under move down or empty place under last item increases height.
In IE8 nothing moves at all... Thanks

<link type="text/css" href="/js/jquery-ui/development-bundle/themes/base/jquery.ui.all.css" rel="stylesheet" />
    <script type="text/javascript" src="/js/jquery.js"></script>
    <script type="text/javascript" src="/js/jquery-ui/development-bundle/ui/jquery.ui.core.js"></script>
    <script type="text/javascript" src="/js/jquery-ui/development-bundle/ui/jquery.ui.widget.js"></script>

    <script type="text/javascript" src="/js/jquery-ui/development-bundle/ui/jquery.ui.mouse.js"></script>
    <script type="text/javascript" src="/js/jquery-ui/development-bundle/ui/jquery.ui.sortable.js"></script>
<style type="text/css">
    #sortable2 { list-style-type: none; margin: 0; padding: 0; zoom: 1; }
    #sortable2 li { margin: 0 5px 5px 5px; padding: 3px; width: 90%; }
    </style>
    <script type="text/javascript">
    $(function() {
        $("#sortable2").sortable({
            cancel: ".ui-state-disabled"
        });

        $("#sortable2 li").disableSelection();
    });
    </script>

<ul id="sortable2">
            <li class="ui-state-default">Item 1</li>
            <li class="ui-state-default ui-state-disabled">(Im not sortable)</li>
            <li class="ui-state-default ui-state-disabled">(Im not sortable)</li>
            <li class="ui-state-default">Item 4</li>
            </ul>