lsinitramfs: 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/lsinitramfs - from package: initramfs-tools

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

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