I pushed a change tonight that makes the database backend even more flexible. You can now use Chyrp with either of the following (it checks in this order):

1. PDO (PDO_MYSQL or PDO_SQLITE[3])
2. MySQLi
3. MySQL
4. Coming soon: SQLite

This addition is still in testing phases (and the installer won’t let you install with the others yet), but it should solve a lot of problems with users on hosts that do not support PDO.