dparsf预处理时总出现这样的错误,不懂,求教

 ??? Error using ==> class

Cannot change the number of fields of class 'file_array' without first
typing 'clear classes'.
 
Error in ==> file_array.file_array at 39
a     = class(a,'file_array');
 
Error in ==> nifti.nifti at 70