I think I know what you're saying. You're wanting the site to show the index page if a url doesn't exist. Basically, let's say someone went to
http://creaturesoflessikor.de/xyz/xyz/xyz and instead of being directed to an error page, you want them redirected to
http://creaturesoflessikor.de
Is that correct? If so, you would probably have to use a .htaccess file in the main directory. I'm not sure what specifically to put in, but I know that's where you'd want to look.