Did as suggested while experiencing the same problem and the incessant misguided warnings, in my case, have stopped. More important to me, however, is why avast has an issue with Apache Web Server. The solution provided did solve the incessant popups, but Avast has never warned me about apache before, and I am (99.999999%) certain that there is no (deliberate) malicious code in the web server software. Also, in case it is relevent, Avast never reported a problem with Apache until today.