The script can work with "globals on" or "globals off". Ideally, the script should run with "globals off", as is the default PHP configuration these days.
What is Globals?
Globals is a technical issue relating to backwards compatibility with PHP.
In the old days of PHP 3, all variables that came from outside were automatically initialized as global variables, and were available to the script without any extra programming effort.
Since about PHP 4, the designers of PHP decided that having 'Globals On' could be a risk for inexperienced programmers, so they decided that future PHP versions should have 'Globals Off' by default. This resulted in many headaches as many scripts were written to rely on 'Globals On' broke.
The Million Dollar Script is compatible with 'Globals On' or 'Globals Off', so this is really not an issue to be concerned about.