Thanks for the reply. Here is a link:
http://www.solborg.fhs.no/album/
I backup the database every day and looking back, it seems the database must have become corrupted somehow. In my backups, the users table is always empty.
The issue now is what to do. I created a new user in phpMyAdmin (because I could not do it via the register script) and assigned group user status to 2, or an admin.
I still can't login. Its a bit strange.
There is only one user, that is the admin who runs the album.
Its a stand alone 4.66, and does not integrate with any forum software or forum user tables.