First step is to get the partiton mounted using loopback mechanism.
Next step is to run graverobber against the mounted image. Note, a lot of the information gathered will not be relevant as it will pertain to the machine the image is mounted on. Next step is to generate a body file that consists of the unallocated inodes on the mounted image. This report references the passwd and group files from the image. The mactime script threw this error and needed a quick fix.