On VSC-2 several versions of MPI are available. Choose one using 'mpi-selector' or 'mpi-selector-menu':

#list available MPI versions:
$ mpi-selector --list
impi_intel-4.1.0.024
impi_intel-4.1.1.036
intel_mpi_intel64-4.0.3.008
mvapich2_1.8_intel_limic
mvapich2_gcc-1.9a2
mvapich2_intel
openmpi-1.5.4_gcc
openmpi-1.5.4_intel
openmpi_gcc-1.6.4

#see the currently used MPI version:
$ mpi-selector --query
default:impi_intel-4.1.0.024
level:user

#set the MPI version:
$ mpi-selector --set impi_intel-4.1.0.024

Modifications will be active after logging in again.