avenger.deliver: 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/avenger.deliver - from package: mailavenger

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

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