fwb_pix: 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/lib/debug/usr/bin/fwb_pix - from package: fwbuilder-dbg
/usr/bin/fwb_pix - from package: fwbuilder

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