klettres: 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/klettres - from package: klettres

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

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