MPI error when running Metadynamics example

Program received signal SIGILL: Illegal instruction.

Backtrace for this error:
--------------------------------------------------------------------------
A process has executed an operation involving a call to the
"fork()" system call to create a child process.  Open MPI is currently
operating in a condition that could result in memory corruption or
other system errors; your job may hang, crash, or produce silent
data corruption.  The use of fork() (or system() or other calls that
create child processes) is strongly discouraged.

The process that invoked fork was:

  Local host:          [[998,1],0] (PID 139023)

If you are *absolutely sure* that your application will successfully
and correctly survive a call to fork(), you may disable this warning
by setting the mpi_warn_on_fork MCA parameter to 0.

title "CH3Cl"
echo
start CH3Cl
scratch_dir ./perm_meta
permanent_dir ./perm_meta
memory 10000 mb

charge 0

geometry units angstrom nocenter noautosym noautoz print xyz
C  0.000000 0.000000 0.000000
Cl 1.799895 0.017342 -0.008727
H -0.323446 -0.918592 0.460310 mass 2.0
H -0.340365 0.851532 0.565115 mass 2.0
H -0.340579 0.057144 -1.020309 mass 2.0
end

nwpw
 simulation_cell units angstroms
  boundary_conditions periodic
  SC 15.0
 end
 cutoff 35.0
 mult 1
 lmbfgs
 mapping 2
 xc pbe96
 lcao_skip
 rotation off
end

#Optimize the wave function
task pspw energy

#CPMD parameters
nwpw
 car-parrinello
  Nose-Hoover 1200.0 300.0 1200.0 300.0
  time_step 5.0
  fake_mass 600.0
  scaling 1.0 1.0
  loop 10 100
  fei equi.fei
  xyz_filename equi.xyz
  ion_motion_filename equi.ion_motion
  emotion_filename equi.emotion
 end
end
task pspw car-parrinello

#Metadynamics begins here
nwpw
 #This is not necessary but I prefer to define separate metadynamics output files
 #Otherwise the metadynamics output will be appended to equi.*
 car-parrinello
  loop 10 2000
  fei meta.fei
  xyz_filename meta.xyz
  ion_motion_filename meta.ion_motion
  emotion_filename meta.emotion
 end
 #Metadynamics block
 metadynamics
  print_shift 1               #prints the bias potential every 1000 time steps
  update 10                   #adds a Gaussian every 10*(inner-loop) = 100 time steps
  bond 1 2 w 0.001 sigma 0.10 #bond distance between C-Cl collective variable
 end
end
task pspw car-parrinello
task pspw car-parrinello
task pspw car-parrinello
task pspw car-parrinello
task pspw car-parrinello
task pspw car-parrinello
task pspw car-parrinello
task pspw car-parrinello
task pspw car-parrinello
task pspw car-parrinello
task pspw car-parrinello