[Freesurfer] extract average thickness using label for every subject

Dear Freesurfer experts,

I have labels representing clusters that I created using mri_surfcluster on sig.mgh file using a specific threshold. Now I want to use these labels to extract average thickness values for every subject. I tried to use mris_anatomical_stats -l $SUBJECTS_DIR/glm/analyza/cllabel-0001.label -t $SUBJECTS_DIR/s0110B/surf/rh.thickness.fwhm10.fsaverage.mgh s0110B rh to calculate it for one subject, but it doesn't work - I get error because the number of vertices in subject's file rh.thickness.fwhm10.fsaverage.mgh doesn't match surface. I should use fsaverage as a subject, right? So I tried mris_anatomical_stats -l $SUBJECTS_DIR/glm/analyza/cllabel-0001.label -t $SUBJECTS_DIR/s0110B/surf/rh.thickness.fwhm10.fsaverage.mgh fsaverage rh but then I get error, that it cannot read fsaverage/mri/wm.mgz file. The wm.mgz file isn't in fsaverage folder.

How can I calculate this?

Thanks for your help!

Patricia