'Scuse the massive *BUMP*!
I'm having this problem as well. The reason I call it a problem is that I am the sole user/account on this computer, not even an active 'guest' account, and all files on the computer were by me, yet I have 262 of these 'err 13' messages so far on the scan... is this still ok??
Cheers
You are still an ordinary user, and there are still many files, owned by the (normally hiddden) superuser account - which aren't (abd shouldn't be) accessible for you. If you want to scan them as well, enable root account and run avast from there. But, this is generally not recommended, because you can fix everything but also easily break everything.
regards,
pc