Well, my FS install is not known as the cleanest in the world, to be sure, so it's a very valid question.
I was also quite fast installing the planes when they were released for FSX, so I might not always have been using the newest installer.
I did however reinstall the B752, removed the aircraft dir and downloaded 'fresh' this monday, just clicking next on the install before I went hunting in the config files and found the 747-400 reference and the flaps setting. I did have a file 'boeing747-400.gau' in the gauges dir, but that did not contain the referenced gauges found in the 'boeing747-400.cab', which added to the confusion. (Not until I installed Panel Studio did it make any sense.)
The flaps setting forum post:
http://www.projectopensky.com/index.php?showtopic=26214 Without using that setting the gauge showing flap angle does not move, but the recorded messages plays as you try to extend the flaps. Also FLogger thinks the flaps extends. However, if you look from the outside the flaps have not extended, and if you try to takeoff, the panel will scream (literally
) warnings at you when you gain speed.
Didn't try reinstalling the F70 though, but the problem I had was exactly the same as Gian, and it was resolved copying the file 737_800 file. (since the overhead and throttle panels points to single gauges from that set) The A321 file is just referenced for HSI and attitude backup gauges.
All the other panels I have installed (I think I might have modded one or two) seem ok, I did check through them quickly yesterday. There were some minor gauges missing here and there, but it looked ok (=flyable).
I tested flying the MD83 and the B763 without problems, so I have no clue on Gians trouble with those.