Well, for me, iPhoto 5 was unusable due to the
Makernote problem which affected a number of brands of camera. It would take 45 minutes to start the program and about the same to quit. iPhoto 6 solves all this (due the the differnt manner in which the Library.iPhoto file works) and I can use the program beautifully with 15,000 images.
Doesn't solve your problem; I'm just reporting that iPhoto 6 did solve some major issues that many people were suffering from.
If you only have 370 images, why not move them all to a new folder on the desktop, scrap your exising library and start again. This will break any Albums which you might have lovingly created, but something is amiss.
(12" G4 Powerbook 10.4)