njb-gettr: 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/njb-gettr - from package: libnjb-tools

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

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