Thanks Bill, for your response.
I'm quite sure it's no coincidence that when investigating the details of the alert, Avast tries to sell me an upgrade to the service to which I now subscribe. The alert always indicates a threat has been detected, not that I've actually had a file infected. And multiple system scans seem to prove that out. I was hoping that the annoying message would eventually go away from some magical fix on your part, or that it would just die on it's own accord. In either case, I'm not too anxious about it at this point, but if it continues much longer I'll try to seriously do something about it. In any event, thanks for your information. I appreciate it.
Paul