arptables-save: 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:

/sbin/arptables-save - from package: arptables_jf

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

On Debian possible default full paths are:

/sbin/arptables-save - from package: arptables

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

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