where did I buy what from?
anyway, esc button works in other applications, no problem. I'll try again later today and see if it works if I push it harder / longer in bttf. sounds weird though, as no other buttons need pushing harder or longer in the game nor in any other application.
thanks for trying to help though. I realize this isn't a usual problem.
update:
seems like I found the problem. apparently, running photoshop CS5 in the background disables the esc button in bttf, for no apparent reason at all. I remembered I had it running yesterday when playing too, so I tried closing it. voila! esc works. and starting photoshop again disables it again, etcetera..
I have no idea why it behaves like this. no big deal, though I do like to just pop into a game for half an hour or two while working. oh well, guess I'll have to do with closing and starting ps in the future

again: thanks to all of you who tried to help.