Aperture 3 does not detect duplicate files on import

Question

On import, AP3 still shows the same files I'm importing from my compact flash card that have already been imported. Raw files are coming from a Nikon D70. This also happens when I try to import photos from an SDHC card coming off from a Canon HFS10 camcorder.
The check mark to "not import duplicate" is checked, yet imported files still show up. I had this same problem before with Aperture 2 and I had to revert back to an older version of CameraRaw -- I believe 2.2 -- to fix the problem.
Need help please.
Thanks.

Answer 1

I was running an up to date version of Aperture 2 on all three of my machines. I upgraded the 17 MBP to Aperture 3. All seemed to function normally. I exported "versions" from an Aperture 2 machine in an attempt to consolidate my libraries. No file names had been changed. "Do not import duplicates" was selected. Aperture 3 wanted to import all files even though some were already present in AP3. I went back and exported "masters" not versions, still saw all files being available for import.
Here is what the AP3 manual says:
"When you import images, Aperture automatically checks to see if any of the images are duplicates of previously imported images. Aperture checks the filename of the master to determine if an image is a duplicate of one in the library. Select the “Do not import duplicates” checkbox to prevent Aperture from importing duplicates. If this checkbox is unselected, Aperture imports all images, even if they are duplicates, and creates a new master with a different name for each duplicate. Aperture never overwrites or replaces a master that has already been imported."
So the question is the "filename" the same. The Finder thinks that the picture file exported from AP2 is exactly the same as the picture file exported from AP3.
Therefore AP3 is not correctly identifying duplicates.