Dear Sungho,
     My student met a problem as follows when she performed temporal processing using sample data (Stroop). Her computer is MaC OS 64 bit. Matlab version is R2014b, Can you help us? Thank you very much!
     Wenhai

Apply a temporal filter to hemoglobin changes...
Warning: Name is nonexistent or not a directory:
/Users/zhuxiaoyu/Desktop/matlab/spm12/external/fieldtrip/preproc
> In path at 109
In addpath at 86
In spm_fnirs_preproc at 108
In spm_fnirs_temporalpreproc_ui at 155
In spm_fnirs>push_temporal_Callback at 70
In gui_mainfcn at 95
In spm_fnirs at 25
In @(hObject,eventdata)spm_fnirs('push_temporal_Callback',hObject,eventdata,guidata(hObject))
Previously accessible file
"/Applications/MATLAB_R2014b.app/toolbox/spm8/external/fieldtrip/preproc/ft_preproc_bandstopfilter.m"
is now inaccessible.

Error in spm_fnirs_preproc (line 119)
Y = ft_preproc_bandstopfilter(Y', P.fs, P.K.C.cutoff(j,:), [],
'fir', fdir)';
Error in spm_fnirs_temporalpreproc_ui (line 155)
[fy, P] = spm_fnirs_preproc(y, P);
Error in spm_fnirs>push_temporal_Callback (line 70)
spm_fnirs_temporalpreproc_ui;
Error in gui_mainfcn (line 95)
feval(varargin{:});
Error in spm_fnirs (line 25)
gui_mainfcn(gui_State, varargin{:});
Error in
@(hObject,eventdata)spm_fnirs('push_temporal_Callback',hObject,eventdata,guidata(hObject))
Error while evaluating UIControl Callback