My original attempt was on my desktop with 16 GBs of RAM. I tried repeating my analysis on my lab's cluster which holds 128 GBs of RAM and the same error occurred. I'm wondering how memory could be a factor.
It seems like AFNI is trying to utilize as much memory available since for some reason it's struggling to warp the anatomical images in this dataset to MNI space. Could the issue have more to do with my anatomical data or the way I'm using SSwarper?