cs,
I've been having problems falling for a few years now. Yes, your right in that when someone or thing distracts me while walking, down I go. My MDS had me go through gait training. We found that because of the PD, I don't lift my right foot high enough to clear the ground when taking a step. Therefore I stub my foot and create a fall situation. To help relieve this problem they had me start saying or thinking " lift your foot when you step". Amazingly it works for me. Now when I become distracted I forget to think "lift your foot when you step".
Lee - made it up - mentioned multitasking. With everything going on in the parky body one little miscue can lead to painful results.
As much as I dislike it, a walker has really helped me with the problem. I would suggest you go see a physical therapist for gait training.

GregD