faust2png: 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/faust2png - from package: faust

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

Error in other languages:
faust2png: bevel nie gevind nie
faust2png: comandă negăsită
faust2png: comando não encontrado
faust2png: commande introuvable
faust2png: command not found
faust2png: käsku ei ole
faust2png: không tìm thấy lệnh
faust2png: komanda nerasta
faust2png: Kommando nicht gefunden.
faust2png: kommandot finns inte
faust2png: komut yok
faust2png: nie znaleziono polecenia
faust2png: níor aimsíodh an t-ordú
faust2png: no se encontró la orden
faust2png: no s'ha trobat l'ordre
faust2png: opdracht niet gevonden
faust2png: parancs nem található
faust2png: perintah tidak ditemukan
faust2png: príkaz nenájdený
faust2png: příkaz nenalezen
faust2png: команда не найдена
faust2png: командата не е открита
faust2png: 命令找不到
faust2png: コマンドが見つかりません