mpp: 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/mpp - from package: makepp

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

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