NPopenmpi2: 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 Debian possible default full paths are:

/usr/bin/NPopenmpi2 - from package: netpipe-openmpi

You may install the required package with command apt-get install {package}

Error in other languages:
NPopenmpi2: bevel nie gevind nie
NPopenmpi2: comandă negăsită
NPopenmpi2: comando não encontrado
NPopenmpi2: commande introuvable
NPopenmpi2: command not found
NPopenmpi2: käsku ei ole
NPopenmpi2: không tìm thấy lệnh
NPopenmpi2: komanda nerasta
NPopenmpi2: Kommando nicht gefunden.
NPopenmpi2: kommandot finns inte
NPopenmpi2: komut yok
NPopenmpi2: nie znaleziono polecenia
NPopenmpi2: níor aimsíodh an t-ordú
NPopenmpi2: no se encontró la orden
NPopenmpi2: no s'ha trobat l'ordre
NPopenmpi2: opdracht niet gevonden
NPopenmpi2: parancs nem található
NPopenmpi2: perintah tidak ditemukan
NPopenmpi2: príkaz nenájdený
NPopenmpi2: příkaz nenalezen
NPopenmpi2: команда не найдена
NPopenmpi2: командата не е открита
NPopenmpi2: 命令找不到
NPopenmpi2: コマンドが見つかりません