Hi Henning,
i think you mean wrong url:
www.domain.de/easyblog
and right url from menu:
www.domain.de/blog
If i'm right, try to check by what data source is generated the url:
www.domain.de/easyblog
There are different approach to exclude urls, for example for data source of type 'contents' you can exclude using categories or single articles, for menu you can exclude using the menu item. For user defained data source a custom filter could be required, based on how the component work.
Best regards
John