Vlk, when I click 'Add/Remove' on the Control Panel I receive the message of a second, incompatible, av program, which is Norton Antivirus/ Internet Security.... This message appears twice! One after another (both are identical). I do not have them!
After that, the Update and Repair proccesses works...
The Change button works too...
The Uninstall I let it to you
I won't try and have to configure avast! again.