downtimed: 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
/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/downtimed - from package: downtimed

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