My recommendation is to do a full, fresh second install in a different location. WIA defaults to the Program Files (x86). If that is where your game resides, install a fresh copy into your Games folder as an administrator. Then update with the latest patch. Try a game to see if you get the same crash.
Assuming you do not, and you shouldn't, then you can copy your file from one version's saves file to the new one and see if the scenario still plays.
This preserves your game, but let's you see if installing and running as an administrator fixes most issues.
Not addressed is your concern about finding the game when you run as an administrator. More on that in a minute.
Look here http://www.ageod-forum.com/showthread.php?26567-Can-t-finde-save