1. Use DVD minus Rs (DVD-Rs) not DVD Plus Rs (DVD+Rs).
2. Taiyo Yuden and Verbatim are the best blank DVD brands.
3. Speed of the DVDs should be 8x to 16x
4. A 4.7 GB is a DVD5 and a 8.5 GB is a DVD9.
5. Make sure to check your burning settings for compatibility with DVD players.
6. Burn at 4x or below, real time

Then there should not be any problem during DVD Duplication.
Call our Atlanta office at 770-451-7400.