I and new to OpenMPI and  have looked for this, but not getting anywhere.

I got an example program off this site:

The compute PI in Fortran example. 

Compiled it with "mpif90" and no errors.
Then used the qsub -I and tried both executing directly and "mpirun" and still receive these errors:

[MGT-2-1:02994] *** An error occurred in MPI_Comm_rank
[MGT-2-1:02994] *** on communicator MPI_COMM_WORLD
[MGT-2-1:02994] *** MPI_ERR_COMM: invalid communicator
[MGT-2-1:02994] *** MPI_ERRORS_ARE_FATAL (goodbye)

Any guidance in the right direction would be appreciated.