Then I noticed the little clock at the bottom ticking away. "Okay", I thought, "it's working..." but 30 seconds later it still hadn't done anything (HN effect?). I'd disable the "go" button on click, and move the clock so that it appear right next to it (instant feedback is nice). You can re-enable the "go" button if any of the parameters change.
Also, in the time its taken me to write this it still hasn't generated any results (Mac 10.5, Safari 4). Don't know if it's me or you.