mpirun doesn't work after upgrade to 9.10

[yesint]

I'm using GROMACS molecular dynamics package, which runs in parallel using mpi. In 9.04 it was running perfectly with
> mpirun -np 4 mdrun_mpi

After upgrade to 9.10 any attempt to run it using mpirun with the number of processors larger than 1 crashes with this message:

----------
The selected RPI failed to initialize during MPI_INIT. This is a
fatal error; I must abort.

This occurred on host semen-home (n0).
The PID of failed process was 10593 (MPI_COMM_WORLD rank: 0)
----------

With -np 1 it works. Serial executable also works. I recompiled GROMACS from source, but it does not solve the problem.
There is some discussion of this error here http://www.lam-mpi.org/MailArchives/lam/2007/04/13094.php but doesn't help.

Version of Ubuntu: 9.10
Version of mpi: liblam4 7.1.2-1.5

[Matthias Heil (m-heil)]

Just to confirm that this is not just a GROMACS problem (whatever
GROMACS is). I have exactly the same problem with a stand-alone
mpi test code that is used as part of oomph-lib to check if
mpi is working

   Matthias

Here's the test code in its entirety:

#include<iostream>

#include "mpi.h"

//========================================================================
/// Minimal mpi self test
//========================================================================
int main(int argc, char **argv)
{

 int myid, numprocs;

 MPI_Init(&argc,&argv);
 MPI_Comm_size(MPI_COMM_WORLD,&numprocs);
 MPI_Comm_rank(MPI_COMM_WORLD,&myid);

 MPI_Finalize();

 std::cout << "This worked" << std::endl;

} //end of main

[yesint (yesint4)]

This bug only affects lam version of MPI (liblam4) for me. mpich is not affected - I removed lam and installed mpich instead and everything works now.