ngetty-helper: 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:

/sbin/ngetty-helper - from package: ngetty

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

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