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

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