Microsoft JScript runtime error: 'Sys.Extended.UI' is null or not an object
<p>i have a problem when on my page when its open its display error message on my page</p>

<p><strong>Microsoft JScript runtime error: 'Sys.Extended.UI' is null or not an object</strong></p>

<pre><code>&lt;ajax:ToolkitScriptManager ID="tsm" runat="server" CombineScripts="false" &gt;

    &lt;/ajax:ToolkitScriptManager&gt;
</code></pre>

<p>and display error </p>

<pre><code>$create(Sys.Extended.UI.ModalPopupBehavior, {"BackgroundCssClass":"modalBackground1","DropShadow":true,"PopupControlID":"ctl00_ContentPlaceHolder1_panelPopupAddDefaultAddress","PopupDragHandleControlID":"ctl00_ContentPlaceHolder1_panelPopupAddDefaultAddressDragHandle","dynamicServicePath":"/SJM.Framework.Website/Order/ActiveOrders.aspx","id":"ctl00_ContentPlaceHolder1_modalPopupAddDefaultAddress"}, null, null, $get("ctl00_ContentPlaceHolder1_hiddenTargetControlForModalPopup"));
</code></pre>

<p>anyone can say me what is the problem i try much but not find </p>
