create_greyscale_module: command not found

Have You tried accessing the binary with the full path?

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/create_greyscale_module - from package: ctn

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