rarp: 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:

/sbin/rarp - from package: net-tools

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

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