rtd: 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/rtd - from package: skycat

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

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