If you meet any trouble copying DVD with the software, please have a try of an alternative method: select ISO File in Target option. This is a way to to copy your original file to hard disc first.
You can then re-burn the ISO to a new blank DVD by Disk Utility: highlight the ISO in “Finder”, right-click it and select “Burn ISO to” option in short-cut menu, insert blank disc to burn.
If the above method does not help, it is highly recommend to test more DVDs, we’d like to know whether this occurs on some special DVD or all DVDs. If it occurs on some special DVD, please contact our Support Center and tell us the DVD details including title, region code, purchasing link from Amazon, etc.