Hmmm, I installed the plugin. I had to manually change the table prefixes and the config file. Then I change the admin login, which forced we to log in again. I was redirected to the WP-security-scan page. But now I cannot access the admin dashboard at all. I changed the admin login back to admin and still no success. It also reported I had no .htaccess file in wp-admin. So I copied one from another installation and modified the AuthUserFile setting accordingly. Having .htaccess present or absent makes no difference.