ddpt: 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 CentOS possible default full paths are:

/usr/bin/ddpt - from package: ddpt

You may install the required package with command yum install {package}

On Debian possible default full paths are:

/usr/bin/ddpt - from package: ddpt

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

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