Lastly, note, that the prefixes are written properly, i.e. IRIs are enclosed in ‘<’ and ‘>’. For some reason my initial copy/paste lost the ‘<’ and ‘>’.
Hey @SPIME
we are using the Jena Framework and the SPARQL1.1 Parser. The given query is actually not a valid SPARQL1.1 query, Virtuoso accepts extended syntax. You can check your query with with http://sparql.org/query-validator.html