Just installed Service Pack 3. I don't see any problems with X10 so far. Everything seems as before - camera works, switches work, etc. I'll report on the macros, timers and the rest later.
Had some problem with the install. After 4 or 5 attempts (anti virus and spyware off & all programs closed) I down loaded the file and still no install. I ran "chkdsk" (chkdsk /f /r C:) at the C: prompt and numerous bad clusters were replaced. Then, the install worked as advertised. I have XP Home Edition, Version 2002, and now Service Pack 3 is installed.