cockpit.sh: 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/jets3t/bin/cockpit.sh - from package: jets3t

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

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