Hi Dieter
I've had a quick look at the EvoLve theme - it looks a nice one.
It looks as if it is quick easy to customize from within its back-end. I have loaded the theme onto my test site on my local computer and the footer appears straight away. Just to test if there is nothing untoward would you please follow the next series of clicks
Goto Appearance=>Theme Options=>Footer
You should see 2 sections
1. Number of widget cols in footer
2. Custom Footer
On install the 2nd one should have this code in its field
<p id="copyright"><span class="credits"><a href="http://theme4press.com/evolve-multipurpose-wordpress-theme/">evolve</a> theme by Theme4Press • Powered by <a href="http://wordpress.org">WordPress</a></span></p>
If it is empty that would explain why you have an empty footer on your site.
I hope this helps but please get back to us if it's more than that
All the best
Dave Foston