Error in bands.x in Quantum Espresso (Error in routine bands (1): reading bands namelist)

Following this web site:
Bandstructure Calculation • Quantum Espresso Tutorial

In the postprocessing using bands.x, there was error.
The input file was like this. pp.bands.silicon.in:

      

&BANDS

  prefix = 'silicon'

  outdir = './tmp/'

  filband = 'si_bands.dat'

/

      

    

Then, we have this error message:

      

     Parallel version (MPI), running on     1 processors
     MPI processes distributed on     1 nodes
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

     Error in routine bands (1):

     reading bands namelist

 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

      

    

But if I add empty line after / in pp.bands.silicon.in, the compile succeeded.
I dont know why