postgreyreport: 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/bin/postgreyreport - from package: postgrey

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

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