I had to tackle this issue on a computer recently. The computer was running Outlook 2003 and AVG 9, but could no longer open Outlook. The first in a series of error messages that popped up when you tried to start Outlook said “Unable to start out-of-process scanning server” then “The add-in “C:\PROGRAM FILES\AVG\AVG9\avgxch32.dll” could not be installed or loaded. This problem may be resolved by using Detect and Repair on the Help menu.” Too bad you cannot get to the help menu in Outlook (although when I finally could, running Detect and Repair didn’t help).
I found one tip that said run the Inbox Repair Tool on the pst file. I did that, it found some errors and repaired them, but the AVG error persisted. Then I found a page on AVG’s site which discussed the problem. The answer was to download a utility to address the problem. The link provided was for AVG 8 (guess this problem’s been around for a while), but I changed the link to reflect AVG 9 and it worked. The utility finally let me start Outlook, but when I restarted, the problem came back. There is a log file generated that you can send to AVG for analysis, but I finally used the utility to get into Outlook and just disabled the AVG add-on. I figure when the next version of AVG comes out, maybe the add-on will work again.