Same problem here. I done a clean install of Windows 7 Ultimate. Within 24 hours the real time sheild was not active. No response from the fix it now button, or by enabling the sheild. Resorted to a complete reinstall of Avast. That fixed it for 36 hours. Turned machine on this morning to find that the real time sheild was once again turned off, and again, no luck at all at turning it back on. This time i will try the method mentioned earlier - the change option in windows control panel. If not, another reinstall will be performed (second within 2 days!).
Problem is, this is not one of my machines, it belongs to someone that is not that good with computers, so i am worried this is going to occur again within a few days. The owner is not going to be too happy to find a problem like this so soon after getting his machine back from me.
Any thoughts or input from an Avast member? Are you guys working on a fix for this seemingly common issue? Do you acknowledge it is a problem?