A recent update to Mac OS X software update includes an update called, Java for Mac OS X 10.5 (or 10.6) Update, that breaks Insight Studio's functionality.
The update prevents Insight Studio from launching. It's only Insight Studio that's affected, the Insight client and Inscribe will still work after the update.
To fix this, open /Applications/Utilities/Java Preferences and check the box next to J2SE 1.4.2.
