runlock: 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/runlock - from package: cronutils

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

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