英文原文及帖子地址：

http://forums.asp.net/1109781/ShowPost.aspx

I have got the same issue. It seems like Visual studio 2005 and the web application pool running ASP.NET 2.0 are having a conflict over the temporary folder.
The workaround I have got for now is:
  - If you have visual studio 2005 is open, close it
  - Go tot the ASP.NET temporary folder for v2.0 of the framework
    <Windows dir>\Microsoft.Net\Framework\v2.0<extra numbers>\Temporary ASpNET pages
  - Remove the folder for your application (or all of them)
  - Reset IIS (on a command line window, >iisreset) [not always needed, but I had to use it sometimes]
  - First Browse your page from IE (http://localhost/your app)
  - Then reopen Visual studio

翻译一下：
1 如果你还开着VS2005，关掉。
2 到ASP.NET的临时目录下面<Windows dir>\Microsoft.Net\Framework\v2.0<extra numbers>\Temporary ASpNET pages
3 删除你的项目的那个目录（或者都删除也行）
4 重启IIS（如果在命令行下输入 iisreset）
5 先打开IE访问你的项目（http://localhost/yourapp）
6 然后再打开VS2005

反正我就这么搞定了，供参考吧