How did you change your web.config file? Did you do the changes described in the user manual or you copy the entire file. It seems that you have changed the original ASP.Net membership providers with our new providers. If you are upgrading a project this is not necessary you can continue using the standard ASP.Net providers. We created our own implementation of Membership Data Providers just to support other databases then SQL Server and to automate the process of creating new databases.