Like the above poster said, you should check your firewall and AV and check to see if the game is allowed as administrator.
If that does not work, take a look at this thread. It consists of a list of helpful programs that may help you get rid of the error. They will also help you increase the over all performance of your computer and help you play AVA.
The program that I would recommend to fix your lag is CCleaner. This program clears out your internet cache as well as your registry and also cleans up your browser cache.
Also, I would recommend Game Booster. This program closes unnecessary programs as well as boosts PC performance all helping you get ingame and get maximum FPS.
Any questions let me know.
Hope that helps