lpg: 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/lpg - from package: lpg

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

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