i get the following memory allocation error for only one out of 20 oasis subjects that i processed with freesurfer 5.1 on an ubuntu 11.10 machine with 24gb memory:

mris_register -curv subjects/OAS1_0061_MR1/surf/lh.sphere templates_freesurfer/lh.KKI_2.tif subjects/OAS1_0061_MR1/surf/lh.sphere_to_KKItemplate.reg
using smoothwm curvature for final alignment
$Id: mris_register.c,v 1.59 2011/03/02 00:04:33 nicks Exp $
  $Id: mrisurf.c,v 1.693.2.2 2011/04/27 19:21:05 nicks Exp $
reading surface from subjects/OAS1_0061_MR1/surf/lh.sphere...
TAGskip: tag=1717658469, failed to calloc 1868656640 bytes!
Cannot allocate memory

system information:

FREESURFER_HOME: /usr/local/freesurfer
Build stamp: freesurfer-Linux-centos4_x86_64-stable-pub-v5.1.0
Debian version: wheezy/sid
Kernel info: Linux 3.0.0-14-generic x86_64

cheers,
@rno