I'm trying to set up the Archivists' Toolkit™, and I keep receiving a message about a problem with the database connection.

If the stacktrace (details) of the message you are receiving contains a line that reads: "java.sql.SQLException: Table '[whatYouNamedYourDatabase].constants' doesn't exist" then you have not initialized the database. To initialize the database in AT version 1.1, use the Maintenance Program. To initialize the database in AT version 1.0, use the AT Initialize Database program. Both of these programs can be found in the same directory as the AT program files.