It may be a corruption on the phone itself, if this comes up when you attach the phone with "sync photo's" enabled. I'd try restoring the phone first.
Something's corrupted in some database or a photo's corrupted somehow is my guess. Is your iPhoto library on the same disk as the system?
Some have found solutions here:
http://discussions.apple.com/thread....sageID=5560672
http://discussions.apple.com/thread....sageID=5228732