This is my first x-10 install, and up until today I've had great success; AHP installed and ran perfectly, lamp modules and single pole switches all work as advertised. The problem I am having is with a 3-way switch (WS-4777), the first one I installed works fine, local and remote from cm15a, the second one though I am running into a rather baffling problem. I wired it up per the directions, and left the switches hanging outside the plastic wall switch box for testing before I buttoned it back up. I first checked local switching, worked fine, tap the master lights come on, go to the slave tap it lights off, repeat in reverse order etc., no problems. Next, go to pc check remote operation through AHP, remote on/off command both work fine. I then place switches back in plastic switch boxes, tap master and slave to ensure connections still good, both work. Go to pc again issue remote command, no go. Both switches still work fine locally, but will only accept remote command when the master is out of the switch box. I double checked (remote command off AHP) a single pole switch on same breaker and it works fine, I'm at a loss as to what could be causing the problem. The master switch is in a single box, but does have quite a bit of wire in it, black and white, twisted and wire nutted together. The 3-way switch controls 4 60w can ceiling lights. I have gone through numerous searches and articles, but haven't seen anything that resembles my problem enough to put me on a troubleshooting path. Any ideas or help would be greatly appreciated. Thank You.