grub-mklayout: 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/grub-mklayout - from package: grub-common

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

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