Hints
The following are some hints to help you identify the problem with the 5 troubleshooting subjects.
Subject 1
The trouble with this subject has occured in the skull stripping step, check the brainmask.mgz volume carefully, comparing it to the T1.mgz volume (loaded in aux) to make sure that the skull has been completely stripped away, leaving behind the complete cortex and the cerebellum.
Subject 2
Subject 3
Subject 4