1. Upload in ASCII/text mode (not binary) especially if written on a Windows system
2. chmod/set permissions to 0755
3. Shebang line of:
#! /usr/bin/perl
4. Before body of the page, output header:
print "Content-type: text/html\n\n";
5. A friend taught me to add:
use CGI::Carp qw(fatalsToBrowser);