It is good to see you could handle some of error. I wonder after you changed the scripts ps_load_initial_gamma and mt_prep_gamma_snap, did you do mt_prep_gamma_snap step again and then just typed stamps??? I see stamps(4,5) so you need to do same steps with new scripts. Also is pscands.1.ij file empty or not?
After you do same steps again you will see psver.mat file, the program could not find this file right now.
Fikret