dpmgr: 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/bin/dpmgr - from package: qdbm-util

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

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