I have created a FQL Query with the Sharepoint Search Query Tool and i get always the a Error 500 SearchServiceExcetpion. And it looks like that the syntax of the query isn't in the right format.
and(path:\"https://myHost/Lists/WKPPR/DispForm.aspx*\")
Solved by adding a FQL result source. Thanks to Mikael Svenson in the comments above.