A few Mac users who have installed the latest OS X 10.6.6 update have found that a few applicaitons, especially iLife applications like iPhoto, will no longer launch. The programs may bounce once or twice and then quit with no indication of a problem. Affected people have tried repairing permissions and starting in Safe Mode, but have not been able to get the programs to work with these methods.
There are a couple of things people can try if their applications are not working.
First check in the Mac App Store to see if the program is available there, and also if the status of the program in the store is set to "Installed." If so then the problem may be with the way the Mac App Store interfaces with the program's licensing. In the Mac App Store, select the program and to the right of the program's page click the "App License Agreement" link. At the bottom of the agreement window click "Done" and the program should now start up.
Other people have had success by reinstalling the affected programs, but of these people a few have run into the same problem after the reinstallation.
Lastly, there appears to be a general compatibility issue that the Mac App Store has with Boot Camp and NTFS partitions. We mentioned this in previous articles (1, 2), and it appears the issue will need to be addressed by Apple in an update to the App Store program, but until then people can get their programs working by ejecting Boot Camp and NTFS volumes from their systems.