NPmpich2: 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/NPmpich2 - from package: netpipe-mpich2

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

Error in other languages:
NPmpich2: bevel nie gevind nie
NPmpich2: comandă negăsită
NPmpich2: comando não encontrado
NPmpich2: commande introuvable
NPmpich2: command not found
NPmpich2: käsku ei ole
NPmpich2: không tìm thấy lệnh
NPmpich2: komanda nerasta
NPmpich2: Kommando nicht gefunden.
NPmpich2: kommandot finns inte
NPmpich2: komut yok
NPmpich2: nie znaleziono polecenia
NPmpich2: níor aimsíodh an t-ordú
NPmpich2: no se encontró la orden
NPmpich2: no s'ha trobat l'ordre
NPmpich2: opdracht niet gevonden
NPmpich2: parancs nem található
NPmpich2: perintah tidak ditemukan
NPmpich2: príkaz nenájdený
NPmpich2: příkaz nenalezen
NPmpich2: команда не найдена
NPmpich2: командата не е открита
NPmpich2: 命令找不到
NPmpich2: コマンドが見つかりません