ddptctl: 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/bin/ddptctl - from package: ddpt

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