also make sure to check if there is a system update, from time to time...rarely, but every now and then mine won't let me open the application unless i update it.
You can access your iPhoto library through Finder. Just go to Pictures->iPhoto Library and the folders should be arranged by date with all of your pictures in them.
no worky with ilife 08. The iphoto library is hidden, invisible.
try to see if you still have those photos in "photobooth" under pictures, then try opening them again with iphoto, maybe it's going to solve your problem