session设置和错误页设置无效
<system.web>
<sessionState mode= "InProc " cookieless= "true " timeout= "30 "/>
<customErrors defaultRedirect= "LoginNotice.aspx " mode= "RemoteOnly ">
</customErrors>
</system.web>

[解决办法]
<!--注释 -->

是不是加在注释里了．