rbootd: 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

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/sbin/rbootd - from package: rbootd

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