Raphael, that depends.
When a version was created from a master/RAW file and it gets corrupted, what got corrupted? In other words, can we go back to the master?
If you see a corrupted version, the chances are high, the original image is corrupted, and thus a corrupted version is computed. You should be able to see this by toggling between original master file and version (press the "M" key). The version is not stored as an actual image file, it is a set of instructions on how to create the version image file by applying adjustments to the original image. These may get corrupted too, if Aperture crashes while writing these instructions. Then you can usually repair this by repairing you Aperture library with the first aid tools. Aperture 3 User Manual: Repairing and Rebuilding Your Aperture Library
Or just discard the version and revert to the original image by using the command "Photos > Revert to original".
To protect yourself against the original images getting corrupted, it is highly recommended to backup your origininal image files right from the card, even before importing to Aperture. Aperture provides a setting to create an backup of the originals while importing. Keep these in a safe place, n addition to your Time Machine backup. But it is not necessary, IMHO, to import the images in duplicates. Then both copies will be on the same disk, and if your disk fails, has bad blocks, etc. both copies might get corrupted at the same time.
Regards
Léonie