[jQuery] Treeview and IE "object doesn't support this object or method"

[jQuery] Treeview and IE "object doesn't support this object or method"


I'm getting this error in IE, but not Firefox.
It borks on this line: $("#pageNav").Treeview({speed: "fast",
collapsed: true, openurl: true});
    <script type="text/javascript" src="/jquery/plugins/
jquery.treeview.js"></script>
    <script type="text/javascript">
        $(function(){
            $("#pageNav").Treeview({speed: "fast", collapsed: true, openurl:
true});
            $("#pageNav").show();
        });
    });
    </script>
Any idea what causes this error?