postfwd1: 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/sbin/postfwd1 - from package: postfwd

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

Error in other languages:
postfwd1: bevel nie gevind nie
postfwd1: comandă negăsită
postfwd1: comando não encontrado
postfwd1: commande introuvable
postfwd1: command not found
postfwd1: käsku ei ole
postfwd1: không tìm thấy lệnh
postfwd1: komanda nerasta
postfwd1: Kommando nicht gefunden.
postfwd1: kommandot finns inte
postfwd1: komut yok
postfwd1: nie znaleziono polecenia
postfwd1: níor aimsíodh an t-ordú
postfwd1: no se encontró la orden
postfwd1: no s'ha trobat l'ordre
postfwd1: opdracht niet gevonden
postfwd1: parancs nem található
postfwd1: perintah tidak ditemukan
postfwd1: príkaz nenájdený
postfwd1: příkaz nenalezen
postfwd1: команда не найдена
postfwd1: командата не е открита
postfwd1: 命令找不到
postfwd1: コマンドが見つかりません