Installing it on my website -->"The page not working, paoloronco.com is not able to menage the request, http error 500"

[paoloronco]

Hello, I'm trying to install formtools on my website, I builded it with NicePage and uploaded it in cPanel offered with domain registration on register.it In the folder public html i have my website and i have installed FormTools in a folder in it.

Now i can access the admin page on formTools, and i'm trying to create a new module with form builder, but when i click "add module" Chrome show "The page not working, paoloronco.com is not able to menage the request, http error 500". Why? How can i solve it?