Most iPhone 4S photos import into iPhoto 11 as all black images
As forbca said in his/her answer in the support thread you linked to, the issue seems to be resolved if you reboot. 

I had the same issue. After a reboot, I'm able to import the photos correctly into iPhoto. Just grab the originals and re-import them in iPhoto. You'll be asked about duplicates – import the portrait photos anyway.

It seems to be a bug in an iPhoto update that only turns up if you haven't rebooted since the update. The corrupted imports were done on a laptop that had over 30 days of uptime.