afni.nimh.nih.gov

So you basically you have a one-way between-subjects ANOVA. Try changing the following

3dMVM -prefix test -jobs 1 \
-model bob \

to

3dMVM -prefix test.nii -jobs 1 \
-bsVars 'bob' \

Also, it would be much faster to simply use 3dANOVA in your case.

Gang