Error downloading image.

I have always imported my new photos & videos (saved to "Cameral Roll" Album)

From "Photos" app on iPad (3rd gen) Wi-Fi + Cellular (VZ), iOS 6

To "iPhoto" app on MacBook Pro, OS X Mountain Lion (10.8.2), 13-inch. Mid2010. 2.4 GHz Intel Core 2 Duo

Via USB (not wi-fi)

A few days ago I imported "selected" photos & videos, as usual, no problem…

The following day I attempted to import of one remaining video, recorded with iPad "Camera" and saved to "Photos" "Camera Roll" Album but received the following message:

"Error downloading image.

iPhoto cannot import your photos because there was a problem downloading an image."

I have attempted the following alternatives (which all generated the same message):

• restarting all devices
• importing to iMovie app
• importing to Preview app

However, I have NOT updated the latest iOS 6.0.1 yet; as I was unsure if this would jeopardize the chances of retrieving (along with the fear of possibly losing) this very important educational video recording (duration - 1 hour: 03minutes: 30seconds).

Please help!

Thank you!!!