When I hover on the Home link, a popup hovers with a Login button. When the login button is pressed, the SCLogin modal is launched. I just want to verify that the register button that you are referring to is the one here?
Looking at the source of your page, this button doesn't look quite right. The href is pointing at "/index.php/de/2015-01-26-09-48-59". However, looking around your page, your registration appears to be at "index.php/de/user-registration", so I'm not sure where that URL value is coming form. Also, there are additional font tags around the button text that did not come from us. Did you customize the module with your own template override?
<a class="btn" href="/index.php/de/2015-01-26-09-48-59"><font><font class="">Register</font></font></a>
Could you also tell me what the values for the following SCLogin module parameters are?
* Login View Settings > Show Register Button
* Registration Component
* Custom Registration Link
I saw your contact us form submission as well. Sorry for the delay in response. Let us know the answers to the above questions and we'll try to help pinpoint the problem.
-Melissa