It wasn’t Avast that was trying to get in my address book, Avast was trying to stop someone!
It seems that I had a Trojan called ‘Win32 Trojan-gen (vc)’
Avast had a bit of trouble with it. It couldn’t delete it or move it to start with. And it kept on turning Avast off when scanning (I was on the net).
But in the end Avast came out the winner of course and managed to move it in to the virus chest.
Still there, but I guess it’s safe for the moment. 