[Freesurfer] fsfast "selxavg-sess" error

hi

i am going over the fsfast tutorial. i have completed all steps up to "FsFastTutorial/905 Average session-level data by condition"

https://surfer.nmr.mgh.harvard.edu/fswiki/FsFastTutorial_2f905_20Average_20s...

when i run "selxavg-sess -sf sessid -df sesspar -analysis sem_assoc", i get the following error:

" ??? Undefined function or variable 'MRIread'.

Error in ==> /usr/local/freesurfer/stable/fsfast/toolbox/fast_selxavg.m On line 160 ==> rstd = MRIread(instem,1);

...

??? Undefined function or variable 'r'.

...

quiting matlab

------------------------------------------ ERROR: fast_selxavg() failed\n ERROR (/autofs/space/engram_012/users/pman/bert-functional): selxavg failed "

can you please tell me why i am getting this error?

thanks paymon hosseini