Have you tried re-importing a few that aren't recognized? This would rule out problems with the drives/readers.
I'm seeing this fairly often with card readers. I don't use DVD's, but it's worth ruling out, imho. You might clean the disks, too. Can you open the unrecognized files in OS X's Preview app?
Good ideas...I'll try them out === I did open the DVDs and brought in the images [because Toast was used to burn them I had to click and drag from DVDs but they all seemed to come in] - I have isolated the 300 or so bad ones and will see if they can be reimported or see what they look like without any Aperture processing..thanks.
I have repaired permissions in the Finder in Show Package Contents on the folder with all the images, I have quit and restarted Aperture, I have repaired permissions in Aperture, rebuilt the database etc. I did identify one of the 400 and pulled it to the desktop and tried to open it with PhotoshopElements9 -= it opened but all as garbage.
I'm now reimporting th eimages to see if there is any change in them between this 'new' library and the old one. The pics are on a set of DVDs that was burned to keep them for the future [HA!] - it was hard enough to get them off the Toast burned disks [proprietary crap] but I was able to do that = but now I have this batch that either ends up blacked out with Unsupported Image Format on front or else looking terribe - like the image was only partly copied over - don't know yet if that's the fault of Toasting or ClickDrag or Aperture = mighe know more once the new batch is imported. Thanks for the help.