Welcome to the Forum.
From the very limited information you have provided the symptom you describe usually indicates that your problem is caused by the use of poor quality DVD media.
Provide the MID (Manufacture ID and Media Code) (Example: TYG03) of the blank DVD Media you are using. To acquire the MID (Manufacture ID and Media Code) (Example: TYG03) of your blank DVD Media use a software utility similar to DVD Identifier (http://dvd.identifier.cdfreaks.com) or DVDInfo (http://www.dvdinfopro.com).
To avoid any confusion state the version number of the software program(s) you are using to make your backup copies.