dh_pyppd: 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_pyppd - from package: pyppd

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

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