mkcramfs: 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/sbin/mkcramfs - from package: cramfsprogs

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

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