Could be several things.
What media are you using, burn speed,errors on the original disc.
Be careful that Roxio and Nero aren't clashing as that has been noted before, I think more with Easy CD/DVD Creator.
I'm not keen on doing disc to disc copyies, I prefer to re-rip the movie back to the hard drive and then just burn another with Nero, or whatever you like to use.
Normally with Roxio (Easy Creator), just make sure the Drag to Disk is turned off. Better yet, not installed on the system. Similar to the InCD with Nero that most people suggest not being loaded or deleted if installed. Batch writing software is a known problem with dvd recording apps. On some systems the Roxio interferes to the extent the entire app may need to be removed. Also, does this happen on all discs you try to copy or just a particular one? You may want to check the source disc with a program like the freeware DVDInfoPro, http://www.dvdinfopro.com .
