Problems importing from iPhone 4 to iPhoto

Question

Really hard problem.  When I first try to import images, I see blank thumbnails on my iPhone -- I click IMPORT and the following error message comes up:
Error Downloading Images
iPhoto cannot import your photos because there was a problem downloading an image.
No matter what iPhone  I plug in (we have three), it shows no thumbnails and it won't download any images.  If I select one image and IMPORT SELECTED, a different error message comes up:
Unreadable Files:  1
The following file could not be imported.  (The file is in an unrecognized format.)
IMG_2965.JPG
First, the file in question is a JPG (I have emailed it to myself to verify that) so it should be in a readable, recognizable format.
Second, it then gives me the option to keep or delete the photos "imported", even though the image didn't import.  I can select either option and the photo count doesn't go down in my iPhone, so in other words, even if I select DELETE, it keeps the images on the iPhone.
Another clue here is that whether or not my iPhone is plugged into the computer, iPhoto shows it as if it is attached.  I can UNMOUNT it but then when I restart iPhoto, it shows it there once again, even if it is still not attached.
Trying to use Image Capture.app resulted in a failure to import as well.  It didn't show thumbnails, but I think that it might not show thumbnails in that software.  Also, if I plug in a different iPhone, it still pretends that my original iPhone, Tango White, is plugged in.
Reading other postings here, I tried already to rebuild the iPhoto databases, thumbnails, etc., by launching iPhoto with the ALT-CMD held down and checking all the boxes.  No luck.  It rebuilds just fine and I still have the same problem.  At this point, we've got three phones and a camera that cannot be imported, with perhaps 2,000 photos in all that we can't seem to bring in!  Seems impractical to email them all one by one.
What is going on and how do I fix it?  The only other clue to the behavior is that no matter which phone I plug in, it appears to think that my original iPhone, Tango White, is still plugged in.
Help!
Thomas.

Answer 1

Hold!  Found another post finally that had the answer -- here it is:
Trash the following file:
com.apple.ImageCaptureNotifications.DeviceDiscoveryDatabase.501
from HD/Library/ Caches
and restart your mac.
That worked PERFECTLY.