Fernando, > Hi Dave. I am using version 1.0.6 over a debian etch cluster with gcc 4.1. 1.0.6 is ancient (more than 3 years old at this point). Can you try the latest release of MPICH2 (1.1.1p1)? -- Pavan -- Pavan Balaji http://www.mcs.anl.gov/~balaji