lua: command not found

Have You tried accessing the binary with the full path?

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/lua - from package: lua

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