VistaDB 2.x used an entirely different file format that is incompatible with the VistaDB 4 and VistaDB 5.  However, there is a 2-step process that will allow you to migrate your data forward to the current VistaDB data format.

Step 1: Migrate VistaDB 2.x data to VistaDB 3.x format

You will need a special utility to perform this data conversion.  You can download the migration tool here:

http://www.gibraltarsoftware.com/docs/default-source/Docs/VistaDB/vistadb20migration.zip

Step 2: Migrate VistaDB 3.x data to VistaDB 5.x format

Once you have converted your VistaDB 2.x database to VistaDB 3.x format, you can use the VistaDB Data Builder tool to upgrade to the latest VistaDB database format.  If you run the VistaB 5 Data Buidler, it will convert data to VistaDB 5.x format.  If you need VistaDB 4.x format, use the Data Builder tool that comes with VistaDB 4.