euca-create-network-interface: 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/euca-create-network-interface - from package: euca2ools

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

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