Procedure

Within the <System.Web> section of the web.config file of the application, clear out the ASP.NET handler, HTTP modules, and remapped tag types that are used in Windows SharePoint Services, and specify the default ASP.NET handler for all pages, by adding lines as follows:

<httpHandlers>
   <clear />
   <add verb="*" path="*.aspx" 
       type="System.Web.UI.PageHandlerFactory, 
       System.Web, Version=1.0.5000.0, Culture=neutral, 
       PublicKeyToken=b03f5f7f11d50a3a" />
</httpHandlers>
<httpModules>
   <clear />
</httpModules>
<pages>
   <tagMapping>
      <clear/>
   </tagMapping>
</pages>

Because Windows SharePoint Services maintains a restrictive trust policy, you may need to adjust the trust level by adding a line like the following to the web.config file of the application.

<trust level="Full" originUrl="" />

You may need to enable the session module by adding the following lines to the web.config file of the application. In the top-level web.config file for Windows SharePoint Services, the default value for the enableSesstionState attribute is false.

<httpModules>
   <add name="Session" 
        type="System.Web.SessionState.SessionStateModule"/>
</httpModules>

Note:
If you receive a parser error message saying that the Session module is already in the application and cannot be re-added, remove the httpModules section.