MagicDraw does not start on Mac OS after QuickTime 7.2 update
This is a known issue in Intel based Mac OS with QuickTime 7.2 update that causes most of the Power PC applications to refuse to start. This problem hounts some Java apps too, and sometimes MagicDraw refuses to start from the icon created by the installer. Although it is possible to start MagicDraw from command line (look for classpath and JVM flags from Indo.plit file).
There is available one solution that fixes the Power PC apps and also the MagicDraw from here: http://mactip.blogspot.com/2007/07/dependent-dylib-is-not-prebound.html
The fix involves some command-line and text editor usage, but it's relatively simple and it works.