Hi, Alex-

Wow, that is embarassing that that message appears in the help file from our build system... I will check that out, thanks for pointing that out.

So, that RetroTS.py program does have pylab as a module dependency. I would have thought installing matplotlib would install that as well, in most situations. Could you perphaps copy+paste the output of:

afni_system_check.py -check_all

on that system? And how would you manage Python module dependencies on that system? Do you use conda, or just module load things?

Minor but useful sidenote: There actually is an afni_proc.py demo of integrating ME-FMRI data with RetroTS.py physio processing, from this OHBM poster:
A multi-echo FMRI processing demo including TEDANA in afni_proc.py pipelines
Paul Taylor, Stephen J. Gotts, Adrian W. Gilmore, Joshua Teves, Richard C. Reynolds
https://afni.nimh.nih.gov/pub/dist/OHBM2022/OHBM2022_tayloretal_apmulti.pdf
... and the demo is downloadable with:

@Install_APMULTI_Demo1_rest

... with both HPC scripts for NIH's Biowulf cluster (scripts_biowulf) and for desktop (scripts_desktop).

In the scripts_desktop_do_14_physio.tcsh, is this example command:

RetroTS.py -prefix ${subj}_${ses}_${task_label} \
           -r ${physio_resp}                    \
           -c ${physio_card}                    \
           -p 50 -n 33 -v 2.2

... where "-v 2.2" signifies a volumetric TR of 2.2s, and "-n 33" means that the volume has n=33 slices. The multi-echo aspect comes in when you process all the EPI information, combining them into a single value per TR (through, for example, optimal combination (OC) or tedana). In the demo, that FMRI processing is done using afni_proc.py and there are various ME-combination methods: OC, old Kundu et al. MEICA and newer MEICA group tedana (mtedana).

--pt