http://www.macnn.com/articles/09/07/27/avg.update.harms.itunes/
Weekend AVG update accidentally targets iTunes
updated 01:25 pm EDT, Mon July 27, 2009
AVG update harms iTunes
A number of Windows iTunes users found their software disabled over the weekend, talk on Apple's support forums reveals. The problem is known to have originated with AVG's antivirus tool, which was recently updated with new virus definitions. The program then mistakenly identified iTunes DLL files as containing the Small.BOG Trojan, and prevented iTunes from working following the quarantine process.
Attempting to reinstall iTunes did not provide a solution. AVG has since produced a new definition update, 270.13.29/2260, which accurately tracks the affected DLL files. Should iTunes continue to be broken, AVG notes that users can go into the Virus Vault option under the History menu, where iTunes files can be manually restored.
Fresh-Faced Recruit
Joined: Jan 2006
buggy
AVG has been suucking lately. The paid version has problems with its firewall component