renamer: 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/renamer - from package: ladr4-apps

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

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