mountpy.py: 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/mountpy.py - from package: mountpy

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

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