Two cents worth trying ...
Hi Delphi,
I am currently away from home and cannot check on the sim, but - if my memory is correct about what I experienced some time ago - here's what I can recall:
Flaps: the default pm sounds setup (as you can see in the PMSounds sounds folder) provides no sounds for the flaps, unless you put some sounds in the pmsound folder AND do some programming of your own.
Of course your FS should play by itself the flap sounds which come along with the active aircraft, but surely not on a client pc (you need pmSounds for that).
Runway bumps: I got accidentally into this, by looking at the "status" window on pmsounds page, that's the box showing the latest sound played by the program. It showed "nbump" but without audible effect. Actually I couldn't recall a nbump.wav file within the pmsounds folder, and in fact there wasn't one. I simply took one suitable elsewhere, copied there and named it nbump.wav, et voilą, the bumps were played and audible.
You may wanna try ...
Cheers,