There is a DateCalc function within Date::Manip. I found the problem, month and day were in the wrong positions (switched) and the difference was returning empty slots instead of numbers for year, month, week, etc..,. Thanks for the reply.
Whoops. Sorry about that. Looking at the doc for the function, that's not much fun. :( If you have Date::Calc or can get it, I'd recommend it strongly over the Date::Manip stuff. DateTime is another excellent choice (slow but *many* features).