Index: lams_learning/src/java/org/lamsfoundation/lams/learning/service/LearnerService.java
===================================================================
diff -u -rfdca3605f0b782b19e214abbe94df6f4a457b88e -r177936f9116cf23277b94131b9562eea6cc6328b
--- lams_learning/src/java/org/lamsfoundation/lams/learning/service/LearnerService.java	(.../LearnerService.java)	(revision fdca3605f0b782b19e214abbe94df6f4a457b88e)
+++ lams_learning/src/java/org/lamsfoundation/lams/learning/service/LearnerService.java	(.../LearnerService.java)	(revision 177936f9116cf23277b94131b9562eea6cc6328b)
@@ -612,7 +612,10 @@
 		if ( lesson.isPreviewLesson() ) {
 			ArrayList<User> learnerList = new ArrayList<User>();
 			learnerList.add(learner);
-			lessonService.performGrouping(grouping, group!=null?group.getGroupId():null, learnerList);
+			if ( group != null && group.getGroupId() != null )
+				lessonService.performGrouping(grouping, group!=null?group.getGroupId():null, learnerList);
+			else 
+				lessonService.performGrouping(grouping, group.getGroupName(), learnerList);
 			groupingDone = true;
 		}
 		return groupingDone;
@@ -994,6 +997,13 @@
     		} else {
 				Group group = lessonService.createGroup(grouping, selectedBranch.getTitle());
 				group.allocateBranchToGroup(null, selectedBranch, branchingActivity);
+				if ( ! forceGrouping(lesson, grouping, group, learner) ) {
+		    		String error = "selectBranch: learner "+learnerId+" cannot be added to the group "+group+" for the branch "
+		    			+selectedBranch+" for the lesson "+lesson.getLessonName()+" preview is "+lesson.isPreviewLesson()
+		    			+". This will only work if preview is true.";
+		    		log.error(error);
+		    		throw new LearnerServiceException(error);
+				}
     		}
 			groupingDAO.update(grouping);