drbl-wakeonlan: 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/drbl-wakeonlan - from package: drbl

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

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