[dnanian]

It certainly looks like that file is bad. You might want to boot from your Tiger install DVD and run Disk Utility from the Installer menu (the bold one that says "Installer" next to the Apple menu at the top of the screen). Then, use the First Aid tab to repair the drive, again using the buttons on the right (NOT Repair Permissions on the left). Repeat until no problems are found, then boot back and try again.

If that doesn't help, I'd suggest going through the Troubleshooting steps in the User's Guide, focusing on the Aperture library. It's going to be a little hard to do, because the library itself is a bundle, and has stuff hidden inside it. (I also don't know what the "AP.Minis" file actually does, so I'm reluctant to suggest deleting it -- but you might want to navigate to it and try to *duplicate* it, should the repair above fail, to see if Finder can read it...)