UPDATE: this seems to be extension-related. Create a shortcut on your desktop to executable “chrome.exe” with the fullpath to the executable pre-fixed, and add command line parameter “–disable-extensions” as shown below:
Doubleclick the icon to fire-up Google Chrome and start browsing. You will notice that the AVG AntiVirus pop-up “We prevented your connection to [site]” no longer shows up. This indicates that the AVG pop-ups are caused by a recently installed or updated Google Chrome extension.