iptables-save: command not found

Have You tried accessing the binary with the full path?

Maybe Your $PATH variable doesn't contain the default paths? echo $PATH should give something like:

[root@server ~]# echo $PATH

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 Debian possible default full paths are:

/sbin/iptables-save - from package: iptables

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