orte-ps: command not found

Have You tried accessing the binary with the full path?

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 Debian possible default full paths are:

/usr/bin/orte-ps - from package: openmpi-bin

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