session设置和异常页设置无效

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．