You're not doing anything wrong. You have missed a few important steps in your settings. In the ConvertxtoDvd window, you'll need to open the Subtitle Stream and through a few steps with right and left clicks of the mouse, work your way through each of those sub menus. Change the language setting for that subtitle when you see the little rectangular window showing "Dutch" in it. Right now your default setting is Dutch, so all foreign language subtitles will show up on your tv/computer screen identified as Dutch, even though you know they're in different languages.