Thanks for the suggestions. I don't understand why telling Web Shield to allow aol.com is "just because," when I did it so Avast would know not to allegedly block aol.com (even though it isn't really blocking it). As I said, aol.com works fine for me, always. The pop-up is erroneous, but it is annoying too.
I'm also not sure why you need a screen shot when I transcribed the pop-up message for you verbatim, but if I'm able to get a screen shot, I'll certainly provide it to whichever specialist I communicate with going forward.
Thanks again for your time. I'll follow the suggestions in the last post above and take it from here.