njb-setowner: 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-setowner - from package: libnjb-tools

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

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