WAT does not work with Ritter or UMBC in ERec experiments

[MichaelRoeder]

When starting an experiment with "Entity Recognition" and "Strong Annotation Match" choosing WAT and Ritter or UMBC, the WAT annotator returns a lot of HTTP 500 errors.

2017-08-10 17:08:19,933 [pool-5-thread-9] ERROR [org.aksw.gerbil.http.AbstractHttpRequestEmitter] - <Response has the wrong status: HTTP/1.1 500 Internal Server Error>
2017-08-10 17:08:19,933 [pool-5-thread-9] ERROR [org.aksw.gerbil.http.AbstractHttpRequestEmitter] - <Response has the wrong status: HTTP/1.1 500 Internal Server Error>
2017-08-10 17:08:19,933 [pool-5-thread-9] ERROR [org.aksw.gerbil.annotator.decorator.ErrorCountingAnnotatorDecorator] - <Got an Exception from the annotator (WAT): Response has the wrong status: HTTP/1.1 500 Internal Server Error>
2017-08-10 17:08:19,933 [pool-5-thread-9] ERROR [org.aksw.gerbil.annotator.decorator.ErrorCountingAnnotatorDecorator] - <Got an Exception from the annotator (WAT): Response has the wrong status: HTTP/1.1 500 Internal Server Error>

http://gerbil.aksw.org/gerbil/experiment?id=201708100001

At the same time, the same experiment has been executed but with the OKE 2016 Task 1 example datasets and it was working without any problems: http://gerbil.aksw.org/gerbil/experiment?id=201708100002