Updated fix
The CHOWN statement has a problem with the parameters. I also noticed after fixing the permissions of the Pictures folder and subfolders (was "700", now "755"), I was still experiencing the iPhoto launch problem.
My solution, after noticing that I could go to Terminal and launch the application from /Applications/iPhoto.app/Contents/Mac OS/iPhoto, was that ownership of the files in the application was not correct.
My fix:
Bring up the Get Info on the iPhoto application in the Applications folder and manually add myself as a user. (I guess you could also add "Everyone".) This solved the issue to me.
Caveat: Launching iPhoto from the old icon on the Dock still returned the error! 😕 I had to launch the application from the Applications folder, then use the Keep In Dock function and trashed the old iPhoto icon.
-Aaron-