What computer operating system is your Premiere Elements 12 running on? Have you updated 12 to the 12.1 Update using an opened project's Help Menu/Update. If not, please do that.
When you burn to disc, are you doing burn to DVD-VIDEO on DVD disc or burn to AVCHD format on DVD disc?
Please determine if you can do a successful burn to folder.
Burn to: Folder (4.7 GB).
or, if you are doing a burn to AVCHD DVD project, then
Burn to Folder (4.7 GB)
There are a lot more questions, but let us get the answers to the above and then we can decide what next.
Do not give up. If you do not understand any of the questions, please do not hesitate to let us know. We will re-write the reply if necessary
to clarify what has been written.