Asp.net-无法加载类型'；MyNameSpace.报告.UI._Default'；

我有一个aspx页面（Project.aspx）和一个aspx.cs代码（Project.aspx.cs）。这个网站安装在客户端，这在以前的时候运行良好。但现在这不起作用，并抛出如下黄页：

---

Server Error in '/mywebcom' Application.
Parser Error
Description: An error occurred during the parsing of a resource required to 
service this request. 
Please review the following specific parse error details and 
modify your source file appropriately. 
Parser Error Message: Could not load type 'MyNameSpace.Reporting.UI._Default'.
Source Error: 

Line 1:  <%@ Page Language="C#" AutoEventWireup="true" EnableEventValidation="false" CodeBehind="Project.aspx.cs" Inherits="MyNameSpace.Reporting.UI._Default" %>
Line 2:  
Line 3:  <%@ Register Src="controls/Search.ascx" TagName="Search" TagPrefix="uc1" %>
Source File: /myweb/tool/reporting/Project.aspx    Line: 1 
Version Information: Microsoft .NET Framework Version:2.0.50727.5448; ASP.NET         
Version:2.0.50727.5456

---

请帮我点什么。非常感谢。

Inherits="MyNameSpace.Reporting.UI._Default"