mmpfb: 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/mmpfb - from package: lcdf-typetools

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

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