Error loading mesh in demo_navier-stokes with mpirun

DOLFIN 1.1 on CentOS 6

Running the first few lines of demo_navier-stokes.py produces a seg fault. In particular

mpirun -n 4 python demo_commented.py

where demo_commented.py is

from dolfin import *

# Print log messages only from the root process in parallel
parameters["std_out_all_processes"] = False;

# Load mesh from file
mesh = Mesh("lshape.xml.gz")

produces the error

$ mpirun -n 4 python demo_commented.py
===================================================================================
= BAD TERMINATION OF ONE OF YOUR APPLICATION PROCESSES
= EXIT CODE: 139
= CLEANING UP REMAINING PROCESSES
= YOU CAN IGNORE THE BELOW CLEANUP MESSAGES
===================================================================================
YOUR APPLICATION TERMINATED WITH THE EXIT STRING: Segmentation fault (signal 11)
This typically refers to a problem with your application.
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