Your mri_glmfit-sim command line is not correct and does not match
examples in the help. Basically you need to spec "--cache 1.3 abs"
not "--cache 1.3 --sim-sign abs"

Thanks Doug, now it worked, however I'm getting this error, which several other people seem to get: "Computing spatial average of each frame
0 1 2*** glibc detected *** mri_segstats: malloc(): memory corruption: 0x2e8df328 ***". I am running FS 5.3.0 through VirtualBox, 2GB ram allocated.

What is your full command line? Sometimes this happens when setting the cwp to 1 (or close to 1).

My command was
mri_glmfit-sim --glmdir /media/math/all38subj/qdec/A2SepGroup_C_DODS_lgi_lh --cache 1.3 abs

therefore I did not change the --cwpvalthresh input argument, meaning cwp presumably stayed at its default of .05.

Terminal output is attached.
What else can I try to make this command work?