Hello Thorsten,
When you set a static front page you can enable slider on it through the meta box, just edit your front page and check the “Agama Options” meta box at bottom of the page.
The theme updates possibly do not work due to the recent migration of our website to a new server but we are working to resolve this matter, until that you can create a temporary admin user/pass for me so I can update the theme for you.
Regards