Index: BH13SPARQLBuilder/src/org/biohackathon/SPARQLBuilder/OWL/OWLClassGraph.java
===================================================================
--- BH13SPARQLBuilder/src/org/biohackathon/SPARQLBuilder/OWL/OWLClassGraph.java (revision 115)
+++ BH13SPARQLBuilder/src/org/biohackathon/SPARQLBuilder/OWL/OWLClassGraph.java (revision 134)
@@ -95,4 +95,5 @@
                       List<ClassLink> crrpath = new LinkedList<>(crrlp.path);
                       crrpath.add(classLinks[j]);
+                      if ( classLinks[j].getLinkedClassURI() == null ){ continue; }
                       if ( classLinks[j].getLinkedClassURI().equals(endClass) ){
                           paths.add(new LinkedList<>(crrpath));