i've upgraded my mac os x snow leopard to lion. besides the new and fancy login screen, the first thing i noticed was that my quicksilver was no longer responding to text inputs. type as much as you want, quicksilver no longer does its magic. i got it working again by doing the following:
˜/Library/Application\ Support/Quicksilver/Triggers.plistthat did the trick for me, hope it does for you too
UPDATE: @LoveQuicksilver responded with: "Rename, don't trash! Bins Triggers."
see also quicksilver issue #429 "Crashes/No Text Input/No Activation after Upgrade to Lion"