Problem running MPI version of NPT

[Rad]

Dear All,

I am trying to perform an NPT ensemble with a MPI compiled code and
run into the following error:

Please set the environment variable MPI_GROUP_MAX for additional
space.
MPI has run out of internal group entries.
Please set the environment variable MPI_GROUP_MAX for additional
space.
The current value of MPI_GROUP_MAX is 512

I have no problem running the calculation with the serially compiled
code (I tried both NPT_I and NPT_F). I tried the MPI run with cell
having 56 atoms, expanded to a supercell with 224 atoms, changed the
ranks to 64, 32, 16, 8, temperatures 2.5 K , 200 K, 300 K, various
pressures (1 bar, 50 bars) etc and I get the same error.

The code is compiled on a IA64 Linux cluster using Intel compiler
(version 9.1).

Please let me know if you have any suggestions and would like to know
whether the NPT portion is tested for different MPI architectures. If
it has been tested on a particular arch let me know I will run it on
the same arch.

Thanks
Rad