Chuck, it was set correctly. For unknown reasons that setting in the mysql database keeps resetting to reviewpost. I didn't change or go into the admin panel.
To reiterate, I had a fully functional working installation and somehow the one field in the db gets reset from phpbb3 to reviewpost. I am the only one with access to the db & server and nothing else was changed. When this happens users get strange error messages in the ReviewPost user interface and I go into the db and change that field back and then everything works fine again.
I am clueless as to why this has happened. It's 4 days later now and I've had no problems.