Just some guesses here....
Judging by your screen name and the use of the word "mains", I'm guessing you are not US based (UK?) - and most X10 equipment, including the CM15A, is designed for US voltages. Some of it can be adapted.
Maybe you are a transplant though......
Also AHP working on Vista still seems to be a challenge - you may wish to read up on these forums about that.
Good Luck,
G