Dear Harleen,
 Although I replaced the spm_fnirs_spm_interp with the update you uploaded before, I stiil meet a problem when I ran the last step (Results button) with the sample data (Stroop) as follows. My matlab version is R2013a. Can you help me ? Thank you very much.
 
Wenhai Zhang
   Statistical Parametric Mapping for Functional Near-Infrared Spectroscopy.
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Interpolate GLM parameters over brain surfaces...
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Load channel-wise parameters...
Reference to non-existent field 'Vres'.
Error in spm_fnirs_spm_interp (line 49)
load(SPM.Vres);
Error in spm_fnirs_results_ui (line 31)
    [SPM] = spm_fnirs_spm_interp(SPM);
Error in spm_fnirs>push_results_Callback (line 88)
spm_fnirs_results_ui;
Error in gui_mainfcn (line 96)
        feval(varargin{:});
Error in spm_fnirs (line 25)
    gui_mainfcn(gui_State, varargin{:});
Error in
@(hObject,eventdata)spm_fnirs('push_results_Callback',hObject,eventdata,guidata(hObject))
 
Error while evaluating uicontrol Callback