error in using ANALYZE format images

Dear all

In REST_V1.4_100420 when I use “Image calculator”  for calculating  the mean(g1)  of ANALYZE format images, the bellow error appeared.

Read 3D EPI functional images: "E:\third-ALFF\mALFF "...

Get the mean value of all the images in E:\third-ALFF\mALFF

??? Error using ==> rest_WriteNiftiImage at 93

Meet error while writing the data

Error in ==> rest_ImgCal_gui>rest_Mean at 509

rest_WriteNiftiImage(meanSeries,Header,[outdir,filesep,outname]);

Error in ==> rest_ImgCal_gui>btnCompute_Callback at 166

            eval(f);

Error in ==> gui_mainfcn at 96

        feval(varargin{:});

Error in ==> rest_ImgCal_gui at 27

    gui_mainfcn(gui_State, varargin{:});

??? Error while evaluating uicontrol Callback

[Fatal Error] :-1:-1: Premature end of file.

Would you please help me?

The other question is related to Ztest in df bottom of slice viewer. Nothing happen, when I set Ztest to 1! What do we expect of this?

thanks