prename: 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/prename - from package: perl

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

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