fw: 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/fw - from package: funnelweb

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

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