I'm probably the last person to figure this out but in case others have problems here it is.
Over several months I have noticed an increase of X10 device operation becoming sluggish and having reduced range. I was about to trash my CM15 because it got to where it would only respond to input from the computer. Then one day a I was testing all of my modules they were doing screwy things like taking repeated commands to work, and hit and miss operation. Then the light bulb came on literally. Over the past year I began replacing the light bulbs in my office where the x10 stuff is located with CFLs. Since I usually turn on lights anytime I'm in the office, the problem got progressively worse. It dawned on me a few months ago and so I turned off all of the CFL lights. Like magic, all of my x10 stuff went back to normal operation. I ran several tests and a little as one 13 watt light will produce enough interference to cause x10 stuff to do odd things. All of the disturbance appears to be only on circuits fed from the same panelboard. CFLs on remote panelboards didn't appear to have much of an effect unless there was an RR501 or TM 751 on it.
