Auto Complete Extender Not Working on Master Page

Hi,
I'm using ajax autocomplete extender(from database). Its working fine in content page. But its not working in Master Page. Help me.... I'm using VS2008. I'm using webservice...


<asp:ScriptManager ID="ScriptManager1"
          runat="server">
     <Services>
     <asp:ServiceReference Path="Autocomplete.asmx" />
     </Services>
     </asp:ScriptManager>


<asp:TextBox ID="txtSearch" runat="server" CssClass="textbox1" Width="400px"></asp:TextBox>
             <cc1:AutoCompleteExtender runat="server"
            runat="server&quo ...