fwbuilder: 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
/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/fwbuilder - from package: fwbuilder

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