Undefined function or variable ‘file array’

              I'm fresher to REST Toolbox. Recently, I use it to compute ALFF. Unfortunately, At first step, it cause an error and promt “Undefined function or variable ‘file array’ ”.
              I tried to find the origin by baidu or google but failed. I think it stemed from wrong data format. The data format used is NIfTI 3D hdr/img pairs which were transformed from nii by MRIcro. My specific setting is "WIN7, REST1.8，MATLAB 2012b". 
             Can anyone solve this ERROR? And tell me how to do next. Thank you !