Dashboard freezes at kpi_drill_down_applet.jsp with Mac Firefox 2.0.0.1. According to Jonathan, it has to do with Firefox not accepting our cookies or something....
Anyways, the fix is easy: upgrade your Mac Firefox to 2.0.0.5.
Yes, that's right. When Java applets (such as the lovely Dashboard Drilldown Applet) make requests for data to the web server, they are supposed to send all the pertinent cookies with the request. It turns out that your Mac version of Firefox 2.0.0.1 wasn't sending any cookies at all!
We haven't done thorough investigation here, so I'm not sure if it was a problem with Firefox 2.0.0.1, or just the Mac variant thereof, or if it was a one-off problem on your machine.
I'm guessing it was probably a FF2.0.0.1 on Mac problem. Anyone who wants to prove me wrong can try this with FF2.0.0.1 on Windows or Linux.