Ah, I think I see what might be happening. There are in fact three different ways by which Quicksilver can look up words in a dictionary:
One is by using a plugin called Dictionary Module. This looks up words by searching dict.org, and adds an action called Define with dict.org, which opens a floating palette window containing the definition(s) of the word found on dict.org. This is working fine on my system. However, Dictionary Module also appears to install two other undocumented actions called Dictionary and Thesaurus which open a different palette window (including a toolbar with buttons). I do not know where it is trying to pull definitions from. This second method does not work on my system. The third method is by installing the Services Menu Module which will add all the Services menu items as actions to Quicksilver, including the Look up in Dictionary action. This is what I use. It was a little flaky on Tiger (as noted in my previous post), but works flawlessly on Leopard. I suggest to you all that you use either the first or third options, and if you choose the first option that you remove the broken actions mentioned in the second option from Quicksilver's list of actions.
