ingo-postfix-policyd: 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 CentOS possible default full paths are:

/usr/bin/ingo-postfix-policyd - from package: php-horde-ingo

You may install the required package with command yum install {package}

On Debian possible default full paths are:

/usr/bin/ingo-postfix-policyd - from package: php-horde-ingo

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