"Calibrating Active Handling" is a normal feature of the car. It's the car recalibrating the active handling system every so often. No problem, I see it about once or twice a month upon cranking up and getting going.
On the other hand, if you saw "Service Active Handling" you may be dealing with a problem.
Be on the lookout for this message as it may indicate a problem with your brake system, Active handling system, or both. There is a TSB and a recall out for the 2005's for a problem with a connector under the steering wheel (steering wheel position sensor) that can make the active handling act wierd based on the car's 'brain' wrongly processing driving conditions...and then applying brakes on its own using the Active Handling System to 'correct' a perceived error in driving. Bad news.
Yours was just probably calibrating itself, which is normal, but I wanted to pass the info along about the "Service Active Handling" message not being a good message to have.
Hope this helps.
If your Service Active Handling come on tow it don't drive it to the dealer. If it kicks in on the Interstate, your in trouble.