I have a similar but even more annoying problem: All the action sounds stop working shortly after loading the game. Whenever I load or quickload a game I can pick something up only once with the correct sound, after that all I can hear is the background music.
This is according to me one of the worst things that could happen since I really miss the sound the 14mm or .223 pistol makes.
Does anyone have the same problem and even more important the solution to this?
(I believe it first happened when I installed FO2, where the same thing occurs, since then both games have no action sounds).