policy-test: 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/policy-test - from package: postgrey

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

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