VPDN is typically used when your client device connects to an access server. What is your setup ? Are you simply trying to connect to an ISP using PPPoE ? And what is your client device/platform (e.g. Cisco 887) ?
dialer interfaces are for routers, I don't even think you can configure those on a ASA. Either way, the link below has sample configs for the ASA as a PPPoE client (since I don't know which OS version you are running: