On a new install of Debian GNU/Linux version 7 (wheezy), after installing apache and mod-perl I am able to use mason, but the SetHandler/PerlHandler directives appear to make the DirectoryIndex directive stop working.
Below are the steps needed to recreate with a fresh Wheezy install.
aptitude install apache2 libhtml-mason-perl libmason-perl
at this point traveling to the server via http should give you the 'It Works Page', and you'll be able to test that DirectoryIndex is working and sending the user to index.html. Add these lines to the default sites-enabled virtual host configuration:
restart apache and now it will parse <% $mason %> on your index, but you will have to travel explicitly to the index (i.e. http://192.168.1.2/index.html) because it will no longer direct you to it automatically.
Thanks in advance for any help with this issue, and my apologies if its far simpler than I thought, or I have somehow not met the standards for a post (I read the rules, but you never can be sure). I have the mason book and have read online documentation, but was unable to find documentation related to apache configuration with mason.