错误: Sys.InvalidOperationException: Handler was not added through the Sys

<%@ Page Language="C#" AutoEventWireup="true" CodeFile="zzdj.aspx.cs" Inherits="Web_mpsp_zzdj" %>

<%@ Register Assembly="AjaxControlToolkit" Namespace="AjaxControlToolkit" TagPrefix="cc1" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">


无标题页



<div>
    <cc1:AutoCompleteExtender ID="AutoCompleteExtender1" runat="server" ServiceMethod="GetCompletionList"
        TargetControlID="TextBox1" UseContextKey="true" CompletionInterval="500" CompletionSetCount="20"
        MinimumPrefixLength="1" ContextKey="k">
    </cc1:AutoCompleteExtender>
</div>
<asp:Label ID="Label2" runat="server" Text="Label2："></asp:Label>
<asp:TextBox ID="TextBox1" runat="server" Width="180px"></asp:TextBox>
<asp:Label ID="Label3" runat="server" Text="Label3："></asp:Label>
<asp:TextBox ID="fz" runat="server" Width="60px"></asp:TextBox>
<asp:Label ID="Label4" runat="server" Text="Label4："></asp:Label>
<%--<asp:TextBox ID="scdw" runat="server" Width="180px"></asp:TextBox>--%>
<asp:DropDownList ID="Ddl_File_path" Style="z-index: -1" runat="server" Width="180px">
</asp:DropDownList>
<asp:Label ID="Label5" runat="server" Text="Label5："></asp:Label>
<asp:TextBox ID="zcs" runat="server" Width="60px"></asp:TextBox>
<asp:Label ID="Label1" runat="server" Text="Label"></asp:Label>
    <asp:Button ID="Button1" runat="server" OnClick="Button1_Click" Text="保存" />
</form>



运行时提示行: 3099错误: Sys.InvalidOperationException: Handler was not added through the Sys.UI.DomEvent.addHandler method.是否要调试此页面？
怎么解决？谢谢！