dh: 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/dh - from package: debhelper

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

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