Despite reinstalling three times my AVG 2012 gives a "General error update failed" and trying to remove various files update has not worked since 10 Feb 2012. I'm running Vista SP2 64-bit and attach the log files I think you need.
But it was very painful to remove all the AVG files from the computer even when logged in as Administrator. To get rid of some of the files/folders you have to go into task manager and stop any avg processes that are running and also turn off User Access Control otherwise they won't delete. Overall I've probably wasted 4-5 hours for £25 of anti virus software!