gummiboot: 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/gummiboot - from package: gummiboot

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

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