Do you have any other burning software on your computer? Some "drag and drop" burning software will take-over your burner.
If that's the problem, there are two possible solutions.
1- Disable the conflicting software.
Or,
2- "Burn" DVD folders to your hard drive, and then copy them to an actual DVD with your other burning software: When you get to the "burn" step, check the box that says
Create DVD folders and un-check
Create Disc. If that works, you'll get the VIDEO_TS and AUDIO_TS folders on your hard drive, instead of on a DVD. And if that works, you have a problem during the actual burning step.
I swear I'm never trying to make a DVD again.
It'll be easier the 2nd time.

Actualy, I understand the feeling... This digital video stuff is not easy! With all of the different file formats, different hardware, different 3rd-party software, and different types/styles of projects, everybody has to figure-out their own procdure that works for their particular situation.
Of course once you get it all figured-out, someone will hand you a different file format or a different type of camera, and you can start all over again!
