livecd-creator: 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/livecd-creator - from package: livecd-tools

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

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