I've been chasing a similar problem for almost a year. My Activity Monitor stops reporting timers and macros, seemingly at random. Usually, re-downloading will fix it, but not always.
When this is happening, timers and macros DO run EXACTLY as they are supposed to, and "external" activity (like commands from hand-held remotes and such) DOES get recorded in the Activity Monitor, it is ONLY timers and macros that stop showing up.
I have been working with "X10 Pro" for almost a year, trying to track down this problem. While some progress has been made (he said the engineers think they know what is causing it), they haven't been able to solve it yet. They are still working on it this very elusive problem. After a LONG series of e-mails yesterday with X10 Pro, I still have confidence that they will keep trying until they can get this problem fixed.