I haven't heard of this problem with ß70. Could you please try the following:
1. Restarting Quicksilver
2. Checking Console.app for any log messages about Quciksilver
3. Restoring the file at ~/Library/Application Support/Quicksilver/Triggers.plist to an earlier version from before ß70 (if you have one, e.g. Time Machine backup)
Let us know how you get on.
Since installing the latest update, all my triggers, both built-in and custom, are showing "Unknown", "Action Missing", and question marks in the setup interface and not working when I try to call them. Wha' happened?