I have the same problem. The option just disappeared suddenly, i used it last night too. Nero gave me this message when I tried to open a DVD project
"No DVD compatible recorder detected.
You can enable DVD based projects by checking the option ‘Enable Image Recorder for all supported media types’ in the application preferences."
Now the “Make DVD” is back but the only thing missing is the editable DVD option. i never used it anyway though. you ahve to make a dvd image and then use regular nero (or another image-buring app to get it onto disc)