Yes, my system day/date/time is correct. I copied/pasted the reg key the same way as I've always been doing for all previous versions of Avast Home before version 4.8. This is a new key I just got. I got 2 of them. But they only work in v4.7. No matter how I copy/paste them into v4.8, I get the "invalid key" message.
Looked at the tutorial. I paste the key exactly as shown in the tutorial. It's not rocket science. The reg key still doesn't work when I try to copy/paste it into v4.8.