I just upgraded to 4.1.1.2 and found that I couldn't open the application. The OS reported that the installation was corrupted. I did a fresh download (as I'd already deleted the DMG files) and tried again, with the same result. I then tried installing the application without subsequently applying the en-GB language pack. All was well. I conclude that installation of the language pack is causing the corruption.
*** This bug has been marked as a duplicate of bug 62442 ***