Actually, I resurrected this ~40 day topic because it was the most recent, and provided a solution that did not work for me. I see from your version 12.2.3126.2 on Win7 and my version 12.2.2276 that they are the same as I put the first part and you put the 2nd/Build part. Settings, About Avast actually shows "12.2.2276 (Build 12.2.3126.2)".
Regardless, maybe the latest works for you but Avast may not be updating XP for this issue. I think my post was still a good idea because it clarified what might be working and what is not working.