nzb: 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/nzb - from package: nzb

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

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