@frank3d:
What's meant by "replacing the AHP file" is that the ActivePhone installer "adds" the extra functions needed for ActivePhone to your computer.
Want to hear the great news though? If you have iWatchMobile/Pro, OnAlert Mobile, MyGarage, HotBodyAlert, or any of the plug-ins working - You are practically using the same thing as ActivePhone! The difference is that ActivePhone will give you a page to control modules with, rather than a camera or security interface. Using version 3.296, it's actually already installed on your computer - the ActivePhone installer would make sure it has the latest ActivePhone file, and then "turn on" the function for you.
A lot of the errors people have seen have been correctable - one person had a firewall so strong it was blocking everything, and a lot of people have trouble grasping networking (I did when I started out with computers).
If you have iWatchMobile working already, then the heavy lifting is done. Purchase/Download/Install ActivePhone, and enjoy.