I've noticed a persistent bug in at least the last few versions of open-mpi.  I'm currently trying to use version 1.5.3 (os-x 10.6, macports installation).

The problem is that the open-mpi module for Fortran 90 is missing functionality that is included in the main library, specifically the MPI_Abort function.  I've attached a very short, simple, test code that will not compile using the openmpi-installed mpif90 script.  In compiling, it gives the error message:

>>  mpif90 test_driver.F90

./test_driver.F90:12.39:
  call mpi_abort(MPI_COMM_WORLD, -1, 0)
                                       1
Error: There is no specific subroutine for the generic 'mpi_abort' at (1)

I am using gfortran version 4.4.6, if that makes any difference, though I anticipate that the problem is that the MPI_Abort function was never included in the F90 openmpi module.  This is currently a show-stopper for me to use openmpi for my research, so until this is fixed, I'll continue to install mpich2 on all of my workstations and clusters.

Thanks for the hard work, and thanks in advance for the continued openmpi development and support,
-Dan