diff --git a/dataload/rdf2json/src/main/java/uk/ac/ebi/rdf2json/annotators/DefinitionAnnotator.java b/dataload/rdf2json/src/main/java/uk/ac/ebi/rdf2json/annotators/DefinitionAnnotator.java
index 564007c6..312c072e 100644
--- a/dataload/rdf2json/src/main/java/uk/ac/ebi/rdf2json/annotators/DefinitionAnnotator.java
+++ b/dataload/rdf2json/src/main/java/uk/ac/ebi/rdf2json/annotators/DefinitionAnnotator.java
@@ -54,7 +54,8 @@ private static void collateProperties(OntologyGraph graph, String destProp, Coll
 						if (value.getType() == PropertyValue.Type.LITERAL ) {
 							listOfValues.add((PropertyValueLiteral) value);
 						} else
-							throw new RuntimeException("Unexpected PropertyValue type = " + value.getType());
+							throw new RuntimeException("Unexpected PropertyValue type = " + value.getType() + " for "
+									+ c.uri + " ontology " + graph.config.get("ontology_purl"));
 					}
 				}
 			}