No-Results Searchpage breaking

On one of my clients pages I experienced a strange bug. When entering a search terms that gets no results, the no-result-page gets broken. In fact, it loads until the wp_head()-statement in the header.php file and crashes at this point.

Somehow this must be related to the flowplayer plugin since after deactivating it, all works fine.

https://wordpress.org/plugins/flowplayer5/