afni.nimh.nih.gov

So you have to do something about that old x86-64 bin.

Maybe that is an old AFNI distribution which is no longer
appropriate. Or maybe it's a non-AFNI directory that yet
contains some old version of nifti_tool.

Consider the output of 'which afni' and 'which nifti_tool'.

Is sbiasfw a different software package that happens to
contain nifti_tool?

- rick