fwb_ipf: 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 Debian possible default full paths are:

/usr/bin/fwb_ipf - from package: fwbuilder

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

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