Hi Mark,
APT and Canon EOS utility shares same library to access the camera. This library has limitation that only one connection can be made in a time.
You are right that the only solution is to close EOS utility before you attempt to make a connection to the camera in APT. On XP there is no crash, but connection can't be made.
So my advice to everybody is same, close EOS utility before using APT (take a look on "Camera Preparation" in User's guide)
P.S. Take a look on the homepage for a list of the new things that are coming