Automatic update at login was what was failing. Went home over lunch and checked. Seems to be working now just fine. (?) Maybe trouble was at other end.
Most probably, anyway you can change the settings of avast4.ini file to configure your installation better.
Into
[InetWD] section you can define
AlwaysConnectedWaitSeconds for the number of seconds to wait before attempting to update.
Into
[AAVM] section you can set
SuppressUpdateErrorInfo and
SuppressUpdatedInfo to have a very silent update.
Click 'Settings' in my signature for more info.