I made the suggested changes and still get "Mozilla does not know how to handle this file type".

The /var/log/apache2/error.log file has only the restart notice at restart time. There are no errors logged during restart.

The display at the bottom of a non existant page and the http://x.x.x.x/server-status pages include "mod_perl", so I still assume that my "apt-get install libapache2-mod-perl2" has worked successfully.