Index: lams_monitoring/src/java/org/lamsfoundation/lams/monitoring/service/MonitoringService.java
===================================================================
diff -u -rd34efdae1ebc6ee4aec70a187bcf396af363e3b1 -r16ea556312dac478f654bac234b1aecbebf049f5
--- lams_monitoring/src/java/org/lamsfoundation/lams/monitoring/service/MonitoringService.java	(.../MonitoringService.java)	(revision d34efdae1ebc6ee4aec70a187bcf396af363e3b1)
+++ lams_monitoring/src/java/org/lamsfoundation/lams/monitoring/service/MonitoringService.java	(.../MonitoringService.java)	(revision 16ea556312dac478f654bac234b1aecbebf049f5)
@@ -95,6 +95,7 @@
 import org.lamsfoundation.lams.monitoring.quartz.job.StartScheduleLessonJob;
 import org.lamsfoundation.lams.notebook.model.NotebookEntry;
 import org.lamsfoundation.lams.notebook.service.CoreNotebookConstants;
+import org.lamsfoundation.lams.rating.model.ToolActivityRatingCriteria;
 import org.lamsfoundation.lams.security.ISecurityService;
 import org.lamsfoundation.lams.tool.ToolContent;
 import org.lamsfoundation.lams.tool.ToolSession;
@@ -1135,6 +1136,9 @@
 	for (Activity activity : learningDesign.getActivities()) {
 	    // get the real object, not the proxy
 	    activity = activityDAO.getActivityByActivityId(activity.getActivityId());
+	    activity.setTransitionFrom(null);
+	    activity.setTransitionTo(null);
+
 	    if (activity.isToolActivity()) {
 		ToolActivity toolActivity = (ToolActivity) activity;
 		// delete content of each tool
@@ -1149,6 +1153,7 @@
 		//  possible nonthreadsafe access to session!!!
 		lessonDAO.flush();
 		Long toolContentId = toolActivity.getToolContentId();
+		lessonDAO.deleteByProperty(ToolActivityRatingCriteria.class, "toolContentId", toolContentId);
 		lessonDAO.deleteById(ToolContent.class, toolContentId);
 	    } else {
 		systemActivities.add(activity);