fwb_pf: 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_pf - from package: fwbuilder

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

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