Author-it v6.0 and later does not support JET libraries. If you are using a JET database, you must switch to a SQL Server database.
You will need to create an empty SQL Server database. If you don't have an existing library, we suggest you import the JET library sample.adl as a starting point. You will find this library included in the data\libraries folder of your Author-it install. This sample library includes templates and sample content for you to get started.