Error using session in IIS 7 - asp.net

Question

After deployment of my website to IIS, I'm getting the following error message when trying to access a session:
Session state can only be used when
enableSessionState is set to true,
either in a configuration file or in
the Page directive. Please also make
sure that
System.Web.SessionStateModule or a
custom session state module is
included in the
\\
section in the application
configuration.
I access it in Page_Load or PreRender events (I tried both versions). With Visual Studio Dev Server it works without a problem. I tried both InProc an SessionState storage, 1 and multiple worker processes. I added a enableSessionState = "true" to my webpage explicitly.
Here is part of web.config:
<system.web>
<globalization culture="ru-RU" uiCulture="ru-RU" />
<compilation debug="true" defaultLanguage="c#">
<assemblies>
<add assembly="System.Core, Version=3.5.0.0, Culture=neutral, PublicKeyToken=B77A5C561934E089" />
<add assembly="System.Data.DataSetExtensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=B77A5C561934E089" />
<add assembly="System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35" />
<add assembly="System.Xml.Linq, Version=3.5.0.0, Culture=neutral, PublicKeyToken=B77A5C561934E089" />
<add assembly="System.Web.Extensions.Design, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35" />
<add assembly="System.Design, Version=2.0.0.0, Culture=neutral, PublicKeyToken=B03F5F7F11D50A3A" />
<add assembly="System.Windows.Forms, Version=2.0.0.0, Culture=neutral, PublicKeyToken=B77A5C561934E089" />
</assemblies>
</compilation>
<pages enableEventValidation="false" enableSessionState="true">
<controls>
<add tagPrefix="asp" namespace="System.Web.UI" assembly="System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35" />
<add tagPrefix="asp" namespace="System.Web.UI.WebControls" assembly="System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35" />
</controls>
</pages>
<httpHandlers>
<remove verb="*" path="*.asmx" />
<add verb="*" path="*.asmx" validate="false" type="System.Web.Script.Services.ScriptHandlerFactory, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35" />
<add verb="*" path="*_AppService.axd" validate="false" type="System.Web.Script.Services.ScriptHandlerFactory, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35" />
<add verb="GET,HEAD" path="ScriptResource.axd" type="System.Web.Handlers.ScriptResourceHandler, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35" validate="false" />
</httpHandlers>
<httpModules>
<add name="ScriptModule" type="System.Web.Handlers.ScriptModule, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35" />
<add name="SearchUrlRewriter" type="Synonymizer.SearchUrlRewriter, Synonymizer, Version=1.0.0.0, Culture=neutral" />
<add name="Session" type="System.Web.SessionStateModule" />
</httpModules>
<sessionState cookieless="UseCookies" cookieName="My_SessionId" mode="InProc" stateNetworkTimeout="5" />
<customErrors mode="Off" />
</system.web>
What else do I need to do to make it work?
I tried to monitor if IIS accesses the aspnet_client folder with Process Monitor and didn't get any access.

Answer 1

The solution happened to be very curious. Though IIS7 jn WIndows 2008R2 in error description says to add SessionStateModule to system.web section, it should be added to system.webServer section.
<system.webServer>
<modules>
<remove name="Session" />
<add name="Session" type="System.Web.SessionState.SessionStateModule, System.Web, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a"/>
</modules>
</system.webServer>

Answer 2

Sessions should work on a plain, empty application. That is, all the default values should work.
If it's not working with basic test applications, then IIS may have got confused with your application.
Try deleting your IIS application. Then create a new virtual directory, restart IIS, and then add your application again.
Also, double check your application's ASP.Net settings. Make sure it's set to the correct version of ASP.Net.
While searching, I also ran into...
http://ramonaeid.spaces.live.com/blog/cns!A77704F1DB999BB0!181.entry
Hope that helps.

Answer 3

Make sure that the service names "ASP.NET State Service" is running and then add this to your web.config.
<sessionState mode="InProc" server="127.0.0.1" port="42424" ... >
Reference:
http://msdn.microsoft.com/en-us/library/ms972429.aspx
http://msdn.microsoft.com/en-us/library/h6bb9cz9(VS.71).aspx
Comment:
Maybe is better to manual change the port to something else. This can be done with regedit.
HKLM\Syste\CurrentControlSet\Services\aspnet_state\Parametres\Port -> 42424
Some more infos:
http://msdn.microsoft.com/en-us/library/ff648667.aspx

Answer 4

Has this particular server been used for anything else? Is it a Windows 2008 server and IIS7?
I'm willing to bet that you're missing some server roles for IIS, have you checked those by right clicking "Computer", choosing "Manage", going to the roles management (it's on the primary tree in computer manager) and checking the installed bits for IIS?
If this is IIS6 then you may have other concerns. But I figure we'll start with something simple, see if we can't help you figure this one out.

Answer 5

What is your folder structure. Do you have web configs at a higher folder that may have explicitly disabled this?
If possible, reregister asp.net
Open Control Panel
Programs\Turn Windows Features on or off
Internet Information Services
World Wide Web Services
Application development Features
ASP.Net <-- check mark here
ref: How to register ASP.NET 2.0 to web server(IIS7)?

Answer 6

Try adding in pages section in web.config the following section:
<namespaces>
<add namespace="System.Web.SessionState" />
<namespaces/>