Namespace in Code Behinde and ASP.Net

[themrthe]

i designed web page and put controls in it , then i added name space to code behind file and add\[code\] <%@ Page Language="C#" AutoEventWireup="true" MasterPageFile="~/Site.master" CodeFile="Default.aspx.cs" Inherits="_Default" %><%@ Register Assembly="AjaxControlToolkit" Namespace="AjaxControlToolkit" TagPrefix="ajaxToolkit" %><%@ Import Namespace="RegisterName" %>\[/code\]to asp file and \[code\] namespace RegisterName { public partial class _Default : System.Web.UI.Page {\[/code\]now i have some Error :\[code\]Error 4 'ASP.default_aspx' does not implement interface member 'System.Web.IHttpHandler.IsReusable'\[/code\]