The DVD part I am unsure of as to either program. However, Roxio has a 'packet writing' program known as DLA or Drag to Disc and Nero uses its own InCD program. These can and do conflict with each other on some machines. Drove me wacky and made lots of coaster CD's. So I completely removed DLA and Roxio from this machine and installed Ashampoo's Burning Studio 6 and have no issues with either CD's or DVD's on either of my Sony drives.
If you go the route I took, you may have to edit the Registry-WARNING-This can be dangerous and is done at your own risk!!! I did edit and removed ALL traces from there and all folders associated with the Roxio program. I even did this on my laptop.
Worth a try. I also recommend, as do others, that you use nothing but quality media. I am having very good luck with Verbatim DVD -R/+R discs.