you could try repairing permissions on the whole disk, using Disk Utility. Not sure it would do anything but it can hurt anything.
When I tried to open iPhoto, there was an error message: "There is a problem accessing one or more files in your iPhoto library. Do you want iPhoto to repair permissions for this library for you?" I selected the repair option but get another message: "iPhoto was unable to repair permissions for the library." I was forced to quit without being able to open iPhoto.