I did remove the $dbh from the subrouting and received an internal server error message.

You need to track down the text of the Perl error which is causing the script to fail and which in turn is causing the web server to display the 'server error' page.

The use CGI::Carp qw(fatalsToBrowser); line you already have should cause the Perl error to be passed to your browser but for some reason that's not happening. Can you get access to the web server's error log file? Or, can you run your script from the command line so the error message come to your terminal window?