Index: lams_central/src/java/org/lamsfoundation/lams/web/controller/LtiController.java
===================================================================
diff -u -rc975a1230b65f2245c5c77ba413afe97a2816df9 -r87104ef92d7624f923876f19145b0b3495bf51fa
--- lams_central/src/java/org/lamsfoundation/lams/web/controller/LtiController.java	(.../LtiController.java)	(revision c975a1230b65f2245c5c77ba413afe97a2816df9)
+++ lams_central/src/java/org/lamsfoundation/lams/web/controller/LtiController.java	(.../LtiController.java)	(revision 87104ef92d7624f923876f19145b0b3495bf51fa)
@@ -120,6 +120,12 @@
 			resourceLinkIdHistory);
 		lesson = lessonService.getLesson(oldExtLessonMap.getLessonId());		
 	    }
+	    
+	    if (lesson == null) {
+		//abort as this is not normal case
+		request.setAttribute("messageKey", "lessonsearch.noresults");
+		return "msgContent";
+	    }
 
 	    String extCourseId = request.getParameter(BasicLTIConstants.CONTEXT_ID);
 	    ExtCourseClassMap currentOrgMap = integrationService.getExtCourseClassMap(extServer.getSid(), extCourseId);