eulb-modify-lb-attributes: 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/eulb-modify-lb-attributes - from package: euca2ools

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

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