What version of Premiere Elements are you using and on what computer operating system is it running?
What are you making copies of..... burn to DVD, Blu-ray, or AVCHD and presumed in the Premiere Elements 11 Publish+Share/Disc/ with number of copies indicated in the burn dialog?
In the past, making disc copies by that process was a hit or miss proposition. If I were you I would consider making exact copies using the software that came with your Blu-ray DVD burner. or DVD/CD burner.
Is your computer optimized?