Dear Freesurfer users,

I try to visualize my longitudinal data for one subject whit the command line given in the freesurfer website:
freeview -v 00049_T1/mri/norm.mgz -f 00049_T1/surf/lh.pial:edgecolor=red 00049_T1/surf/rh.pial:edgecolor=red 00049_T1/surf/lh.white:edgecolor=blue 00049_T1/surf/rh.white:edgecolor=blue            

I can open the norm.mgz but then the sofware crash for pial and white surf!
I have that error message:                                                            
MatrixMultiply: m2 is null!

I don't understand where the problem is? Can somebody help me?
Thanks for all,
Charlotte