lcg-gt: 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/lcg-gt - from package: lcg-util

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

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