Loss of keyboard assignments - the installer programs?

A while back there was a short thread about lost keyboard assignments - in particular the key for frame rate and a couple of others. I had this problem, and another user suspected it was the SceneryUSA demo, which I'd also installed. Last night I noticed that my Pushback key (the standard Shift-P) was no longer assigned, along with Ctrl-Shift_F1 for fuel cutoff.The only thing that I'd done that was the slightest bit unusual was install the nice Dusseldorf (EDDL) scenery which was posted a few days back. Like SceneryUSA, this was not a simple Zip, but instead a self-installer EXE program. I suspect the Installer is the problem, but I've got no way to verify it. Anybody else have this problem with self-installers?