The fact that they work properly locally says to me that the wiring is o.k. It sounds like you have signal problems. I don't know how many or what kind of X-10 devices you have installed in your house, but you need to run basic tests for signal and noise to try to find your problem. I first started with a couple of switch's and they worked perfectly, after adding more things down the road I began to have many problems. I installed a phase coupler/repeater and tested signal with a meter. I had to filter all tv's, power strips, and computers after these steps I have perfect results every time and I have over 25 switch's and modules at this time (all switchlinc) I searched for you model switch and they don't seem to be the best of quality, perhaps a switchlinc or pcs would work better for you.