"Repair" means:
*. Click "Control Panel"
*. Click "Programs and Features"
*. Right-Click "Avast {Free} Antivirus"
*. Click "Repair"
*. Click "Continue"
I did the above, and then applied KB3000850, and everything seems to be OK.
Thanks AVAST:
Anyone who understands the complexity of the modern private (pc, Mac, etc) environment greatly appreciates the speed with which you tackled and repaired this problem.
Paul