Well, as far as I know, most of the addresses that are stored on the CT file is/are not working anymore. The one that the thread starter was telling you to do was for your HP/MP values to update and reflect on your Cheat Engine. Most of the addresses on them don't work anymore.
If you did it like how you have said it, then that's correct. Opening up the CT by clicking on the folder button then attaching the Cheat Engine to the Dragon Nest executable by clicking on the process button (The one that glows red/green).
You'll just need to use a different one .