rlock: 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/rlock - from package: ruby-lockfile

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

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