I had something similar happen a few weeks ago, but not due to power outages.
I found one evening that NONE of my X10 stuff was working via remotes or the CM15A. However, local control of wall switches still worked. I guessed that something was generating a lot of powerline noise.
I set up a test rig using a surge protector, with only a TM751 and an appliance module plugged into it. I could take that to any outlet, and determine if the noise was affecting that outlet. If a handheld remote couldn't turn the module on, then there was a lot of powerline noise at that outlet. As a control, plugging the strip into a FilterLinc allowed it to work, as it kept the noise from infiltrating the test rig.
To test, I plugged my test rig into an outlet near the breaker box, and started shutting off circuit breakers one at a time, and trying to turn my appliance module on and off. Lucky for me, the first breaker I tried was the culprit!
Once I found the offending circuit, I was able to test each device on that circuit until I located the noisy one.
It turns out that I had a Compact Flourescent bulb in one of my outdoor fixtures that had gone bad, and started creating enough powerline noise that all X10 signals were blocked in the entire house (both phases!).
I unscrewed the bulb, and everything returned to normal.
What was strange was that it was the same exact bulb I have in all 6 of my outdoor fixtures, and this is the only one that went bad.
Since the package said it was guaranteed for 7 years, I took it back to Home Depot, and they gladly exhanged it for a new one. No more problems.
Perhaps the frequent power outages you experienced caused some device of yours to go flaky.
I hope that helps you in some way.
--Noam