Iphoto does not recognize video files when the iphoto library is on an external drive
I have copied my iphoto library to an external hard drive. I pointed iPhoto to the new location. I can import photos with no problem, but when I try to import video files (from my iPhone or from another drive) I get a message that the file is not recognized. When I moved the iphoto library back to the MAC hard drive, the import works OK both for photos and videos.
I am using iphoto 11 and all the videos were taken with my iphone.
Any ideas?
iPhoto '11, OS X Mountain Lion (10.8.2)