AJAXControlToolkit: Only one instance of a ScriptManager can be added to the page

Hi 

i use 2 file upload control in my page.

<asp:ToolkitScriptManager ID="ToolKitScriptManager2" runat="server"></asp:ToolkitScriptManager>
<asp:UpdatePanel ID="Upbdt1" runat="server">    
    <ContentTemplate>
    <asp:ModalPopupExtender DropShadow="true" ID="ModalPopupExtender1"  
            PopupControlID="PnPopup" runat="server" TargetControlID="BtnPopup">
    </asp:ModalPopupExtender>
    <asp:Button ID="BtnPopup1" OnClick="BtnPopup_Click" runat="server" Text="select image" CssClass="DPC9_Img1" BorderStyle="Solid" BorderWidth="0px" BorderColor="White" />
    <asp:Panel ID="PnPopup1" runat="server" BackColor="White"  
            CssClass="panel">
        <asp:ImageButton ID="ImageButton2" runat="server" ImageUrl="~/image/close.png" />
        <br />
        <asp:FileUpload ID="AsyncFileUpload2" runat="server"/>
        <asp:Button ID="BtnUpload1" OnClick="BtnUpload_Click"  runat="server" Text="up load" />
    </asp:Panel>
    </ContentTemplate>   
    <Triggers>
        <asp:PostBackTrigger ControlID="BtnUpload1" />    
    </Triggers>    
</asp:UpdatePanel>

I wrote these code twice in my page but when i run page this error occur.

Only one instance of a ScriptManager can be added to the page.

Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code. 

Exception Details: System.InvalidOperationException: Only one instance of a ScriptManager can be added to the page.

 now what should i do?

 Thanks