Moving this discussion to the Adobe Camera RAW forum.
Either your camera raw is somehow not ACR 7.3, still, or your files are corrupted. Do a Help / About Plug-in / Camera Raw in Photoshop to see what version is reported.
If you have used Nikon Transfer V1 then Nikon has said that it corrupts files from the very newest Nikon cameras. You can test this by transferring your NEF files by something other than Nikon Transfer—perhaps Explorer or Finder and see if they import, then. The newer Nikon Transfer that is part of ViewNX2 does work ok with new camera files.
You can correct the corruption on already transferred files using a utility from the following page: http://owl.phy.queensu.ca/~phil/exiftool/fix_corrupted_nef.html
If you have not used Nikon Transfer V1 and your camera-raw is indeed ACR 7.3, then reply back with version details and perhaps a sample file for others to inspect, uploading to www.dropbox.com and posting a public download link if necessary