Since I haven't done this DTS conversion, I'm in the dark too. The conversion instructions specifically say to use Megui version 0.3.0.0, which should have both Aften and ffmpeg in the tools folder of Megui.

Here is the link for 0.3.0.0
http://www.digital-digest.com/softwa...4&ssid=0&did=5

Let me know if this helps.