dpns-mkdir: 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/dpns-mkdir - from package: dpm

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

On Debian possible default full paths are:

/usr/bin/dpns-mkdir - from package: dpm

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

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