euca-delete-network-acl-entry: 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-delete-network-acl-entry - from package: euca2ools

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

On Debian possible default full paths are:

/usr/bin/euca-delete-network-acl-entry - from package: euca2ools

You may install the required package with command apt-get install {package}

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