Put more details in the error message for next time

git-svn-id: https://svn.apache.org/repos/asf/poi/trunk@1124622 13f79535-47bb-0310-9956-ffa450edef68

src/ooxml/java/org/apache/poi/openxml4j/opc/OPCPackage.java

@@ -160,7 +160,10 @@ public abstract class OPCPackage implements RelationshipSource, Closeable {
 		} catch (InvalidFormatException e) {
 			// Should never happen
 			throw new OpenXML4JRuntimeException(
-					"Package.init() : this exception should never happen, if you read this message please send a mail to the developers team.");
+					"Package.init() : this exception should never happen, " +
+					"if you read this message please send a mail to the developers team. : " +
+					e.getMessage()
+			);
 		}
 	}