Difficult to say what is the reason for this burning issue.
First of all I would recommend checking different disks from different manufacturers.
There are many different kind of disk which are not always fully compatible due to different standards during the manufacturing.
I made good experience using –R disks (CDs and DVDs) from TDK.
Then you should also check the registry and should remove (delete if available) upper and lower filters from the following registry key:
i dont know if your issue has been resolved, but i think you may try another dvd authoring program like Imgburn (free), though its interface can be a bit daunting maybe.
Or use DVD Creator to convert and burn movies onto DVD disc.