title: Object reference error during custom session state provider initialization
body: <p>I have written a custom session state provider which works fine in debug mode but once deployed on the server (IIS 6) i get the following error:</p>
  
  <pre><code>Event code: 3008 
  Event message: A configuration error has occurred. 
  Event time: 10/7/2011 3:05:02 PM 
  Event time (UTC): 10/7/2011 9:35:02 AM 
  Event ID: 00e2c8b1368b45608bb062eb2ba9d0db 
  Event sequence: 2 
  Event occurrence: 1 
  Event detail code: 0 
  
  Application information: 
      Application domain: /LM/W3SVC/1/Root/bizapp-1-129624536989844520 
      Trust level: Full 
      Application Virtual Path: ...
      Application Path: ...
      Machine name: ...
  
  Process information: 
      Process ID: 7556 
      Process name: w3wp.exe 
      Account name: ...
  
  Exception information: 
      Exception type: ConfigurationErrorsException 
      Exception message: Object reference not set to an instance of an object. (E:\Program Files\BizAPP\WebClient\web.config line 282) 
  
  Request information: 
      Request URL: http://localhost:8080/bizapp/login.aspx 
      Request path: /bizapp/login.aspx 
      User host address: 127.0.0.1 
      User:  
      Is authenticated: False 
      Authentication Type:  
      Thread account name: ...
  
  Thread information: 
      Thread ID: 1 
      Thread account name: ...
      Is impersonating: False 
      Stack trace:    at System.Web.Configuration.ProvidersHelper.InstantiateProvider(ProviderSettings providerSettings, Type providerType)
     at System.Web.SessionState.SessionStateModule.InitCustomStore(SessionStateSection config)
     at System.Web.SessionState.SessionStateModule.InitModuleFromConfig(HttpApplication app, SessionStateSection config)
     at System.Web.SessionState.SessionStateModule.Init(HttpApplication app)
     at System.Web.HttpApplication.InitModulesCommon()
     at System.Web.HttpApplication.InitModules()
     at System.Web.HttpApplication.InitInternal(HttpContext context, HttpApplicationState state, MethodInfo[] handlers)
     at System.Web.HttpApplicationFactory.GetNormalApplicationInstance(HttpContext context)
     at System.Web.HttpApplicationFactory.GetApplicationInstance(HttpContext context)
     at System.Web.HttpRuntime.ProcessRequestInternal(HttpWorkerRequest wr)
  </code></pre>
  
  <p><strong>EDIT</strong>
  line 282 is from web.config having the provider info, 3rd line below </p>
  
  <pre><code>&lt;sessionState mode="Custom" customProvider="SessionStateStoreProvider" timeout="180"&gt;
              &lt;providers&gt;
                  &lt;add name="SessionStateStoreProvider" type="type full name" /&gt;
              &lt;/providers&gt;
          &lt;/sessionState&gt;
  </code></pre>