pvserver_openmpi: command not found

Maybe Your $PATH variable doesn't contain the default paths? echo $PATH should give something like:

[root@server ~]# echo $PATH
/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin

If it's empty, You may set the PATH variable with this command

export PATH="/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin"

On CentOS possible default full paths are:

/usr/lib64/openmpi/bin/pvserver_openmpi - from package: paraview-openmpi

You may install the required package with command yum install {package}

Error in other languages:
pvserver_openmpi: bevel nie gevind nie
pvserver_openmpi: comandă negăsită
pvserver_openmpi: comando não encontrado
pvserver_openmpi: commande introuvable
pvserver_openmpi: command not found
pvserver_openmpi: käsku ei ole
pvserver_openmpi: không tìm thấy lệnh
pvserver_openmpi: komanda nerasta
pvserver_openmpi: Kommando nicht gefunden.
pvserver_openmpi: kommandot finns inte
pvserver_openmpi: komut yok
pvserver_openmpi: nie znaleziono polecenia
pvserver_openmpi: níor aimsíodh an t-ordú
pvserver_openmpi: no se encontró la orden
pvserver_openmpi: no s'ha trobat l'ordre
pvserver_openmpi: opdracht niet gevonden
pvserver_openmpi: parancs nem található
pvserver_openmpi: perintah tidak ditemukan
pvserver_openmpi: príkaz nenájdený
pvserver_openmpi: příkaz nenalezen
pvserver_openmpi: команда не найдена
pvserver_openmpi: командата не е открита
pvserver_openmpi: 命令找不到
pvserver_openmpi: コマンドが見つかりません