"A serious bug in a component of the new AVG 2011 anti-malware products causes computers to flood websites with unnecessary HTTP requests and in many cases prevents users from properly using their browsers.

It appears that the bug is located in the LinkScanner component, which is found in the entire AVG 2011 product line, including the company's popular free antivirus.

... end users are most affected in all this, because their browsers will open tens or hundreds of connections in the background and will become unresponsive.

Reports suggest other usability issues as well. For example, users not being able to use certain features on legit websites like YouTube, or the IE7 compatibility mode being broken for IE8 users."

Full read:
http://news.softpedia.com/news/AVG-2011-Bug-Affects-Browsing-Experience-Could-Also-Hurt-Websites-160515.shtml

At the bottom of the above linked page, see also "More Related Articles" on other recent AVG False positive detections.