I think that specific error means that the kernel decided to allow you to run afni (i.e. it isn't a permissions problem), but that the kernel couldn't figure out how to start it. I haven't run into that one before.
On recent Ubuntu/debian the xorg7 versions work (I use xorg7_64). Have you tried that version? I'm doubtful that would cause this particular problem, though. Are you extracting the tar.gz files under linux or under windows and transferring them somehow? Is /software a separate filesystem? The outputs of these commands in linux could help rule answer some of these questions:
uname -a
mount
ls -l /software/afni/afni
file /software/afni/afni
file /bin/bash
--judd