On what computer operating system is your Premiere Elements 13 installed?
Like all Premiere Elements projects, the setup of the project plays an important part in the outcome.
What are the properties of the source media that you placed on the Premiere Elements 13 Timeline?
What project preset did you (manually) or the project (automatically) set to match the properties of that source media?
How did you decide to export the Timeline content?
Export to file save to the computer hard drive? If so, please detail the settings....Publish+Share/Computer/ then what? What did you
set for Presets? Did you use the default settings for the preset or customize them under the Advanced Button/Video Tab of the preset?
Burn to Disc.....DVD-VIDEO on DVD disc, AVCHD format on DVD disc, or Blu-ray disc format on Blu-ray disc?
And, what specific Instance Movie theme did you use?
Let us start here and then decide what next.