Unable to find the requested .NET framework data provider. It may not be installed.

Hi,
After reading almost all the content that can be found about this problem and trying everything that does not sound dangerous for production server i decide to post my question here with all Stack Trace info that i am getting.
Can someone advice me what to do?

Stack Trace:

[ArgumentException: Unable to find the requested .Net Framework Data Provider.  It may not be installed.]
   System.Data.Common.DbProviderFactories.GetFactory(String providerInvariantName) +1044767
   WebMatrix.Data.DbProviderFactoryWrapper.CreateConnection(String connectionString) +64
   WebMatrix.Data.<>c__DisplayClass15.<openconnectionstringinternal>b__14() +16
   WebMatrix.Data.Database.get_Connection() +19
   WebMatrix.Data.Database.EnsureConnectionOpen() +13
   WebMatrix.Data.<queryinternal>d__0.MoveNext() +67
   System.Linq.Enumerable.FirstOrDefault(IEnumerable`1 source) +121
   WebMatrix.Data.Database.QuerySingle(String commandText, Object[] args) +100
   WebMatrix.WebData.DatabaseWrapper.QuerySingle(String commandText, Object[] parameters) +14
   WebMatrix.WebData.SimpleMembershipProvider.CheckTableExists(IDatabase db, String tableName) +54
   WebMatrix.WebData.SimpleMembershipProvider.CreateTablesIfNeeded() +50
   WebMatrix.WebData.WebSecurity.InitializeMembershipProvider(SimpleMembershipProvider simpleMembership, DatabaseConnectionInfo connect, String userTableName, String userIdColumn, String userNameColumn, Boolean createTables, SimpleMembershipProviderCasingBehavior casingBehavior) +82
   WebMatrix.WebData.WebSecurity.InitializeProviders(DatabaseConnectionInfo connect, String userTableName, String userIdColumn, String userNameColumn, Boolean autoCreateTables, SimpleMembershipProviderCasingBehavior casingBehavior) +54
   WebMatrix.WebData.WebSecurity.InitializeDatabaseConnection(String connectionStringName, String userTableName, String userIdColumn, String userNameColumn, Boolean autoCreateTables, SimpleMembershipProviderCasingBehavior casingBehavior) +55
   ApniSi.AuthConfig.RegisterAuth() +47
   ApniSi.MvcApplication.Application_Start() +155

[HttpException (0x80004005): Unable to find the requested .Net Framework Data Provider.  It may not be installed.]
   System.Web.HttpApplicationFactory.EnsureAppStartCalledForIntegratedMode(HttpContext context, HttpApplication app) +10093517
   System.Web.HttpApplication.RegisterEventSubscriptionsWithIIS(IntPtr appContext, HttpContext context, MethodInfo[] handlers) +118
   System.Web.HttpApplication.InitSpecial(HttpApplicationState state, MethodInfo[] handlers, IntPtr appContext, HttpContext context) +173
   System.Web.HttpApplicationFactory.GetSpecialApplicationInstance(IntPtr appContext, HttpContext context) +218
   System.Web.Hosting.PipelineRuntime.InitializeApplication(IntPtr appContext) +296

[HttpException (0x80004005): Unable to find the requested .Net Framework Data Provider.  It may not be installed.]
   System.Web.HttpRuntime.FirstRequestInit(HttpContext context) +10074716
   System.Web.HttpRuntime.EnsureFirstRequestInit(HttpContext context) +95
   System.Web.HttpRuntime.ProcessRequestNotificationPrivate(IIS7WorkerRequest wr, HttpContext context) +254

What I have tried:

I did try to set "DbProviderFactories" in the web.config but it goes with 500 error :(

Tags: .NET