We are using mpich2-1.4.1p1. I can give a try with the latest version. My job script is as follows:

#!/bin/sh
#PBS -N asyn
#PBS -q batch
#PBS -l nodes=4:ppn=4
#PBS -l walltime=120:00:00
#PBS -V
cd $PBS_O_WORKDIR
mpirun -np 16 gmx_mpi mdrun -deffnm asyn_10ns