[Freesurfer] extract thickness values for vertex

Dear FreeSurfers,

Is there a way to extract thickness values for individual subjects for a vertex that are obtained after analyses with mri_glmfit? I have seen a script that does this with qdec - but most of the analyses I run are on mri_glmfit, so was wondering if the script on the user contribution section needs to be modified for mri_glmfit. I ran the script where the output files are located and get the following error:

ERROR: failure writing ./media...../fsaverage/surf/lh.1.mgh

Reading group avg surface area 864 cm^2 from file

mghRead( /media/...../fsaverage/suf/lh.1.mgh, -1) : could not open file

Is this simply a permission issue with the fsaverage folder?

Thanks for your help,

Prapti