live-update-initramfs: 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:

/bin/live-update-initramfs - from package: live-tools

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

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