grub-file: 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-file - from package: grub-common

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

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