rmilter: 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/rmilter - from package: rmilter

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

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