ok...I removed them and now i get this error when i try to upgrade is:

Server Error in '/' Application.
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The files '/App_Code/RazorHelpers/Facebook.cshtml' and '/App_Code/IFrame/Providers/DataProviders/SqlDataProvider/SqlDataProvider.vb' use a different language, which is not allowed since they need to be compiled together.
Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: System.Web.HttpException: The files '/App_Code/RazorHelpers/Facebook.cshtml' and '/App_Code/IFrame/Providers/DataProviders/SqlDataProvider/SqlDataProvider.vb' use a different language, which is not allowed since they need to be compiled together.

Source Error:

An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below.  

Stack Trace:


[HttpException (0x80004005): The files '/App_Code/RazorHelpers/Facebook.cshtml' and '/App_Code/IFrame/Providers/DataProviders/SqlDataProvider/SqlDataProvider.vb' use a different language, which is not allowed since they need to be compiled together.]
   System.Web.Compilation.BuildProvidersCompiler.ProcessBuildProviders() +628
   System.Web.Compilation.BuildProvidersCompiler.PerformBuild() +46
   System.Web.Compilation.CodeDirectoryCompiler.GetCodeDirectoryAssembly(VirtualPath virtualDir, CodeDirectoryType dirType, String assemblyName, StringSet excludedSubdirectories, Boolean isDirectoryAllowed) +11557229
   System.Web.Compilation.BuildManager.CompileCodeDirectory(VirtualPath virtualDir, CodeDirectoryType dirType, String assemblyName, StringSet excludedSubdirectories) +181
   System.Web.Compilation.BuildManager.CompileCodeDirectories() +498
   System.Web.Compilation.BuildManager.EnsureTopLevelFilesCompiled() +762

[HttpException (0x80004005): The files '/App_Code/RazorHelpers/Facebook.cshtml' and '/App_Code/IFrame/Providers/DataProviders/SqlDataProvider/SqlDataProvider.vb' use a different language, which is not allowed since they need to be compiled together.]
   System.Web.Compilation.BuildManager.ReportTopLevelCompilationException() +100
   System.Web.Compilation.BuildManager.EnsureTopLevelFilesCompiled() +1126
   System.Web.Hosting.HostingEnvironment.Initialize(ApplicationManager appManager, IApplicationHost appHost, IConfigMapPathFactory configMapPathFactory, HostingEnvironmentParameters hostingParameters, PolicyLevel policyLevel, Exception appDomainCreationException) +1209

[HttpException (0x80004005): The files '/App_Code/RazorHelpers/Facebook.cshtml' and '/App_Code/IFrame/Providers/DataProviders/SqlDataProvider/SqlDataProvider.vb' use a different language, which is not allowed since they need to be compiled together.]
   System.Web.HttpRuntime.FirstRequestInit(HttpContext context) +11700896
   System.Web.HttpRuntime.EnsureFirstRequestInit(HttpContext context) +141
   System.Web.HttpRuntime.ProcessRequestNotificationPrivate(IIS7WorkerRequest wr, HttpContext context) +4869125

 


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Version Information: Microsoft .NET Framework Version:4.0.30319; ASP.NET Version:4.0.30319.272

If you usiong the install package you have to transfer same of the old web.config values e.g. Connection strings, Maschine key, paths to non compiled modules, databaseOwner and objectQualifier manuelly from the old to the new one. 

But you are more care to do upgrades with the upgrade package!