tune-clientdir-opt: 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/share/drbl/sbin/tune-clientdir-opt - from package: drbl

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

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