Open RTE was unable to open the hostfile

After running job.sh script i receive the following error:

Open RTE was unable to open the hostfile:
    -np
Check to make sure the path and filename are correct.

Here is job.sh

  1 #!/bin/bash
  2 
  3 #PBS -l nodes=${NODES}:ppn=${PPN},walltime=00:01:00
  4 #PBS -N lab
  5 #PBS -q batch
  6 
  7 cd $PBS_O_WORKDIR
  8 mpirun --hostfile $PBS_NODEFILE -np $((NODES * PPN)) main ${ARG1} ${ARG2}