gfxboot: 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/gfxboot - from package: gfxboot

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

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