Is this shown when you're using Build mode? If so, it's normal, as the data you're adding will fit on a CD, thus a DVD isn't needed. May I guess you're trying to burn video(s) to watch on a standard DVD player? If this is the case, you'll need to convert those videos to DVD-Video format, which you can do by using DVD Flick. If it's something else, feel free to ask how to do it (have a look in the Guides section for even quicker help )
By the way, to see the real capabilities of your drive, you can go to Tools/Drive/Capabilities