herclin: 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 CentOS possible default full paths are:

/usr/bin/herclin - from package: hercules

You may install the required package with command yum install {package}

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