Normally when this happens it means that there’s been some corruption in your database, and you’ll need to restore from backups.
You do have backups, don’t you? 😉
Thanks for the reply.
These files are from a backup.
If the other required files aren’t there then there’s not much you can do. If they are gone and not backed up somewhere, they are gone for good.
This is one reason that I always try to recommend doing an SQL dump for backups instead of backing up the database files. MySQL can be a bit funny about exchanging files sometimes, so I’ve always found it a much safer option to export and import SQL rather then the raw files.