IPhoto does not recognize old backup of library

Question

I have a iPhoto library backup disk (dvd) that dates back to 2006. Iphoto does not recognize the photos and they will not open. How do I get to see the photo's?
Iphoto 11
iMac 2.4 ghz intel core duo
OS 10.6.8

Answer 1

The only thing I can think of is that the Library is corrupted in some way. Unusual that the main computer can access it - though it rebuilds the thumbs each time, whiile the other two cannot. I suspect that the permissions warnings are bogus.
Neither of the other machines would be able to read that library without updating it, and in fact, once the 9.5.1 version updates it, the 9.4.3 version wouldn't  be able to read it either.
But either way, each library should ask to upgrade it upon opening, that the don't suggests that the Library is damaged.
You need to decide what version you want to want to view this library with - as you can't view it with either of the other two once you upgrade it. Then from that machine rebuild the Library with iPhoto Library Manager.
Download iPhoto Library Manager and use its rebuild function. (In early versions of Library Manager it's the File -> Rebuild command. In later versions it's under the Library menu.)
This will create an entirely new library. It will then copy (or try to) your photos and all the associated metadata and versions to this new Library, and arrange it as close as it can to what you had in the damaged Library. It does this based on information it finds in the iPhoto sharing mechanism - but that means that things not shared won't be there, so no slideshows, books or calendars, for instance - but it should get all your events, albums and keywords, faces and places back.
Because this process creates an entirely new library and leaves your old one untouched, it is non-destructive, and if you're not happy with the results you can simply return to your old one.