Hi Andre, Could you check with our MVAPICH folks? There are a bunch of things that may cause issues not related to the MPICH code integrated into MVAPICH, so they may be able to provide you with a better support for your issue. In fact, the missing environment variable is likely to be related to the process manager, and you might be using mpirun_rsh, which is not developed by us. Antonio On Wednesday, June 26, 2013 10:29:37 AM Andre Pattantyus wrote: Hello, I am running a numerical dispersion model on a linux cluster with mvapich-1.2.0 and pgi/10.2 compiler. I am trying to submit a job on 8 processors with code written by the developer but I keep getting errors. Right now I am getting the following error when the executable hycm_std gets called: /share/huina/akp4221/hysplit/trunk/exec/hycm_stdPMGR_COLLECTIVE ERROR: unitialized MPI task: Missing required environment variable: MPIRUN_RANK I do not have root privileges but I would like to know what the potential issues I could be facing so I can let the administrator now. -- Andre PattantyusGraduate Student Research AssistantDepartment of MeteorologyUniversity of Hawaii at Manoa2525 Correa Rd, HIG 350Honolulu, HI 96822Phone: (845) 264-3582