Patrick: Lvood's approach may work. For what it's worth, I had the exact same problem- older triggers worked fine, but any trigger that opened up a site would revert to null whenever I restarted my machine. I did some tests, and it would revert to null when I just quit Quicksilver. The solution that worked for me was replacing the plist (which was corrupted).
ikisai - The link to lovequicksilver.com works for me, and should still be up. I'm seeing it here.
