Could not create the driver from NHibernate.Driver.MySqlDataDriver

Here a piece of #C code, I use to create session for NHibernate:

1. Configuration config = new Configuration();
2. config.Configure();
3. ISessionFactory factory = config.BuildSessionFactory();
4.......

Line 3 would raise error something like "Could not create the driver from NHibernate.Driver.MySqlDataDriver"

I pointed to Mysql.Data.dll file in References folder on the Solution Exploreror, than change Copy Global property from false to true. The code could work to open a session.