iPhoto exclamation mark, out of possible solutions

Hi there,

Yesterday I found out that a big part of my iPhoto-library is broken. I can see thumbnails of all my pictures, but when I click to enlarge them, I get an exclamation mark. When I select a photo and try to get to the original file in Finder, I get notified that the file can't be found.

Of course this is a big problem for me, I've stored photos in there since 2008.

I've looked all over the web for possible solutions to this problem, like holding CMD+ALT to get the iPhoto recovery tools. With these tools I've tried to repair and rebuild the database and also tried to repair the permissions. This didn't do anything for me.

Then I downloaded the iPhoto Library Manager and tried to build a new database, based on the original one. It got about 30% of the pictures, unfortunately these are the pictures that are still available to me anyhow. I noticed that the new database has a size of about 6GB, while my original database weighs about 18GB. Is this an indication the photo's are still available, or could the difference in size just be other things like trash, duplicates, etc?

Another solution could've been my Time Machine, but unfortunately my copies reach back to a few months and the oldest Library-file has the same problems.

Is there anyone out there who has other suggestions for me? At this moment I'm copying the database to an external disk to test it on another Mac, but I'm not very confident about a positive outcome. By the way, I'm using iPhoto 9.5.