SPEX Reduction: 

I.  Made flats.   5 of each set of flats were medianed and normalized
	files: flat1.fits:   files 1029-1033   worked 
               flat2.fits;   files 1152-1156   failed
               flat3.fits:   files 1171-1175   worked

Could not make the flat2: 
Scaling the flats...
% Program caused arithmetic error: Floating divide by 0
% Program caused arithmetic error: Floating underflow
% Subscript range values of the form low:high must be >= 0, < size, with low
  <= high: MASK.
% Execution halted at:  SCALESPECSKY      103
  /usr/local/Spextool/pro/scalespecsky.pro
%                       XSPEXTOOL_MKFLAT 1811
  /usr/local/Spextool/pro/xspextool.pro
%                       XSPEXTOOL_EVENT   299
  /usr/local/Spextool/pro/xspextool.pro
%                       WIDGET_PROCESS_EVENTS       
%                       $MAIN$