Help! Importation Demo doesn't work…

Hello

It is my first site with “Enfold”. I would want to import the demo “health”. I went to “Enfold” > ” demo Importer ” > I choose the demo. And I have an error message:
“Importing didnt work!
You might want to try reloading the page and then try again
(The script returned the following message:

Avia Framework “avia_featured_media” already exists.
Fichier média “” already exists.”

I look for somebody who could help me. I am lost and I do not understand how I can make.

Thank you for answering me because I am blocked.