iphoto deleting info

I've been using iphoto '08 on my iBook G4 and lately during the editing process all of the data in the image file gets deleted. This used to be a sporadic problem but it is now a constant problem.

For example, I start the post process with a 3.5MB file, make the desired changes, and somewhere along the line it deletes ALL of the information for that image, not just the changes. When I get out and try to come back in to the image file there's no information at all- the the file has 0kb of data. The image shows up in the event feed but no longer exists as a file. Anyone else ever have this problem?

Sounds like it is having trouble writing back the changes to the disk, which could be indicative of a permission problem (easy to fix) or a dying hard drive (harder to fix because changing the HD in an iBook G4 is a PITA).

Can you "revert to original" and everything is okay (but unmodified obviously)?

Yes, I can revert to original. Thanks for suggesting that (I thought I had tried that but, apparently not) because I thought a couple of those files had been lost forever.

I've tried making fewer changes to see where it all goes bad and any change at all results in the same problem. Where do I go to try fixing a permission problem?

First, I would open Disk Utility and have it repair the drive's permissions there.

Second, I would make a complete backup of the drive.

Third, I would launch iPhoto with the command and option keys held down and check every box in the resulting dialog, then let it complete that work. For good measure, restart after that.