aptd: 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/sbin/aptd - from package: aptdaemon

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

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