vbutil_kernel: 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/vbutil_kernel - from package: vboot-kernel-utils

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

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