[Freesurfer] error message on "make_average_volume"

Dear freesurfer expertise:

When I perform the make_average_subject to obtain the custom average template, I encountered following error message in make_average_volume step: ---- Loading mask /usr/local/freesurfer/subjects/avgsubject/mri/brainmask.mgz ninput = 64 Chcking inputs Checking 0 /usr/local/... ... Checking 63 /usr/local/... nframestot = 64 Allocing output MRIalloc(256, 256, 256): could not allocate 262144 bytes for 11578 slice

Cannot allocate memory ERROR: make_average_volume ----

Does that mean insufficient memory? or something wrong within my data? All subjects finished recon-all step without error and the "make_average_surface" step also finished without any error.

Thank you for any advise.