Aperture Has Lost My Images (the masters!)

Yesterday, my girlfriend and I used my laptop as part of a school assignment of hers along with a Canon 5D. We were able to shoot over 300 pictures over four hours. Every once in a while, I would adjust levels on a recently shot image. We stopped tethering, disconnected the camera and closed Aperture. We started to go through the photos tonight but many photos are displaying the Unsupported Image Format message. I knew that Aperture doesn't support many camera RAW formats, but I knew it did support the 5D. It turns out that the RAW files are completely missing from the database, though there are thumbnails for them. I can't export a master or a version of the majority of the images that were shot.

Here's me browsing for them in Terminal, you can see that a large portion of the images are completely missing:

alpha:~ brianpuccio$ cd Pictures/Aperture\ Library.aplibrary/Misc/Allison\ Photo\ Class\ Tether.approject/
alpha:Allison Photo Class Tether.approject brianpuccio$ ls
2009-10-27 @ 07:06:32 PM - 1.apimportgroup AP.Tinies
2009-10-27 @ 07:08:05 PM - 2.apimportgroup Album.implicitAlbum
AP.Minis Info.apfolder
AP.Thumbnails
alpha:Allison Photo Class Tether.approject brianpuccio$ cd 2009-10-27\ \@\ 07\:06\:32\ PM\ -\ 1.apimportgroup/
alpha:2009-10-27 @ 07:06:32 PM - 1.apimportgroup brianpuccio$ ls -al
total 0
drwxr-xr-x 6 brianpuccio staff 204 Oct 27 19:07 .
drwxr-xr-x 9 brianpuccio staff 306 Oct 28 18:02 ..
drwxr-xr-x 9 brianpuccio staff 306 Oct 27 19:07 IMG_0001
drwxr-xr-x 9 brianpuccio staff 306 Oct 27 19:06 IMG_0002
drwxr-xr-x 9 brianpuccio staff 306 Oct 27 19:07 IMG_0003
drwxr-xr-x 9 brianpuccio staff 306 Oct 27 19:07 IMG_0004
alpha:2009-10-27 @ 07:06:32 PM - 1.apimportgroup brianpuccio$ cd ../2009-10-27\ \@\ 07\:08\:05\ PM\ -\ 2.apimportgroup/
alpha:2009-10-27 @ 07:08:05 PM - 2.apimportgroup brianpuccio$ ls -al
total 0
drwxr-xr-x 40 brianpuccio staff 1360 Oct 28 18:02 .
drwxr-xr-x 9 brianpuccio staff 306 Oct 28 18:02 ..
drwxr-xr-x 9 brianpuccio staff 306 Oct 27 19:19 IMG_0018
drwxr-xr-x 9 brianpuccio staff 306 Oct 27 19:20 IMG_0019
drwxr-xr-x 9 brianpuccio staff 306 Oct 27 19:20 IMG_0020
drwxr-xr-x 9 brianpuccio staff 306 Oct 27 19:20 IMG_0021
drwxr-xr-x 9 brianpuccio staff 306 Oct 27 19:20 IMG_0022
drwxr-xr-x 9 brianpuccio staff 306 Oct 27 19:21 IMG_0023
drwxr-xr-x 9 brianpuccio staff 306 Oct 27 19:21 IMG_0024
drwxr-xr-x 9 brianpuccio staff 306 Oct 27 19:22 IMG_0026
drwxr-xr-x 9 brianpuccio staff 306 Oct 27 19:24 IMG_0027
drwxr-xr-x 9 brianpuccio staff 306 Oct 27 19:24 IMG_0028
drwxr-xr-x 9 brianpuccio staff 306 Oct 27 19:24 IMG_0029
drwxr-xr-x 9 brianpuccio staff 306 Oct 27 19:25 IMG_0030
drwxr-xr-x 9 brianpuccio staff 306 Oct 27 19:26 IMG_0031
drwxr-xr-x 9 brianpuccio staff 306 Oct 27 19:28 IMG_0032
drwxr-xr-x 9 brianpuccio staff 306 Oct 27 19:29 IMG_0033
drwxr-xr-x 9 brianpuccio staff 306 Oct 27 19:30 IMG_0035
drwxr-xr-x 9 brianpuccio staff 306 Oct 27 19:31 IMG_0036
drwxr-xr-x 9 brianpuccio staff 306 Oct 27 19:31 IMG_0037
drwxr-xr-x 9 brianpuccio staff 306 Oct 27 19:32 IMG_0038
drwxr-xr-x 9 brianpuccio staff 306 Oct 27 19:32 IMG_0039
drwxr-xr-x 9 brianpuccio staff 306 Oct 27 19:33 IMG_0040
drwxr-xr-x 9 brianpuccio staff 306 Oct 27 19:34 IMG_0041
drwxr-xr-x 9 brianpuccio staff 306 Oct 27 19:34 IMG_0044
drwxr-xr-x 9 brianpuccio staff 306 Oct 27 19:34 IMG_0045
drwxr-xr-x 9 brianpuccio staff 306 Oct 27 19:35 IMG_0046
drwxr-xr-x 9 brianpuccio staff 306 Oct 27 19:35 IMG_0047
drwxr-xr-x 9 brianpuccio staff 306 Oct 27 19:45 IMG_0048
drwxr-xr-x 9 brianpuccio staff 306 Oct 27 19:52 IMG_0061
drwxr-xr-x 9 brianpuccio staff 306 Oct 27 20:24 IMG_0074
drwxr-xr-x 9 brianpuccio staff 306 Oct 27 21:07 IMG_0159
drwxr-xr-x 9 brianpuccio staff 306 Oct 27 21:07 IMG_0160
drwxr-xr-x 9 brianpuccio staff 306 Oct 27 21:27 IMG_0173
drwxr-xr-x 9 brianpuccio staff 306 Oct 27 21:29 IMG_0178
drwxr-xr-x 9 brianpuccio staff 306 Oct 27 21:29 IMG_0179
drwxr-xr-x 9 brianpuccio staff 306 Oct 27 21:29 IMG_0180
drwxr-xr-x 9 brianpuccio staff 306 Oct 27 21:29 IMG_0181
drwxr-xr-x 9 brianpuccio staff 306 Oct 27 21:30 IMG_0182
drwxr-xr-x 9 brianpuccio staff 306 Oct 27 21:30 IMG_0183