is the key stuck and the steering lock on as well? - any of these help? - not too keen on the 1st one - trust MB to just "show it the hammer!"......
I have a Mercedes-Benz S500 and it was stuck in park and a MB tech told me to pump the break while hammering the shifter with a mallet and yanking the shifter down (all at the same time). I had my Dad continuously press the break while I hammered and yanked that blasted shifter down to Drive. As odd as that sounds, it works. But this is just temporary.
I had a similar problem. I couldn't take my car out of park. The problem was a brake switch that is connected to the brake pedal. You normally step on the brake to place the car in gear. If the switch goes out and you step on the brake the trans will not engage. Don't know if this is same situation with your car.
You may not have any problem at all. Your wife might have put the car in park and let the car roll before engaging the hand brake. If your car rolled while in park and the weight of the car leaned on the parking brake you may need to push the car a little bit before it can get out of park. depending on the car the push may need to be a little or a lot. Next time follow this as a parking routine: reverse or drive into parking spot, stop, with foot still on the brake pedal put car in park and engage hand brake fully so that car doesn't roll. Remove foot from brake pedal. This should stop that problem.
On my 1994 Toyota Corolla, when I had this problem and couldn't get the gear shift to budge, the tow truck driver showed me an override switch, which was located above the gear shift under a plastic tab. ( You need something like a key or screwdriver to depress it, but it gets you out of park and I was able to drive to the garage to get the "brake light service switch" fixed. It's a temporary fix, but it works!
Here is a site that will help clear things up:
www.autoshop101.com/forms/h18.pdf (You must have Adobe Acrobat Reader to access the information.) It is roughly page three that covers the "shift lock release button" and the shift solenoid. If you have a this "release" or "override" button it is almost certain that it is the shift lock solenoid. A failing solenoid can be affected by temperature variations. I hope this will help all that reads; it helped me. Philsy