diff --git a/calendar/event.php b/calendar/event.php
index 7031a87d455..eb4ba6db9f9 100644
--- a/calendar/event.php
+++ b/calendar/event.php
@@ -39,9 +39,9 @@
 /////////////////////////////////////////////////////////////////////////////
 
     require_once('../config.php');
-    require_once('lib.php');
-    require_once('../course/lib.php');
-    require_once('../mod/forum/lib.php');
+    require_once($CFG->dirroot.'/calendar/lib.php');
+    require_once($CFG->dirroot.'/course/lib.php');
+    require_once($CFG->dirroot.'/mod/forum/lib.php');
 
     require_login();
 
diff --git a/calendar/preferences.php b/calendar/preferences.php
index 194f3f4b632..5a134a3e742 100644
--- a/calendar/preferences.php
+++ b/calendar/preferences.php
@@ -1,9 +1,8 @@
 <?PHP  // $Id$
        // preferences.php - user prefs for calendar
 
-    require("../config.php");
-    require_once('lib.php');
-
+    require_once('../config.php');
+    require_once($CFG->dirroot.'/calendar/lib.php');
 
     if (isset($SESSION->cal_course_referer)) {
         if (! $course = get_record("course", "id", $SESSION->cal_course_referer)) {
@@ -17,7 +16,7 @@
 
 /// If data submitted, then process and store.
 
-	if ($form = data_submitted()) {  
+	if ($form = data_submitted()) {
         print_header();
         foreach ($form as $preference => $value) {
             switch ($preference) {
diff --git a/calendar/set.php b/calendar/set.php
index 78d40f5bd86..470bd736396 100644
--- a/calendar/set.php
+++ b/calendar/set.php
@@ -39,7 +39,7 @@
 /////////////////////////////////////////////////////////////////////////////
 
     require_once('../config.php');
-    require_once('lib.php');
+    require_once($CFG->dirroot.'/calendar/lib.php');
 
     require_variable($_GET['from']);
     require_variable($_GET['var']);
diff --git a/calendar/view.php b/calendar/view.php
index eb6042c5867..243eebdf3b5 100644
--- a/calendar/view.php
+++ b/calendar/view.php
@@ -41,8 +41,8 @@
 //  Display the calendar page.
 
     require_once('../config.php');
-    require_once('../course/lib.php');
-    require_once('lib.php');
+    require_once($CFG->dirroot.'/course/lib.php');
+    require_once($CFG->dirroot.'/calendar/lib.php');
 
     optional_variable($_GET['view'], 'upcoming');
     optional_variable($_GET['course'], 0);
@@ -117,7 +117,8 @@
     // but NOT for the "main page" course
     if($SESSION->cal_course_referer > 1 &&
       ($shortname = get_field('course', 'shortname', 'id', $SESSION->cal_course_referer)) !== false) {
-        // If we know about the referring course, show a return link
+        // If we know about the referring course, show a return link and ALSO require login!
+        require_login();
         $nav = '<a href="'.$CFG->wwwroot.'/course/view.php?id='.$SESSION->cal_course_referer.'">'.$shortname.'</a> -> '.$nav;
     }
 
diff --git a/course/view.php b/course/view.php
index c945d5431bd..029261194c9 100644
--- a/course/view.php
+++ b/course/view.php
@@ -2,9 +2,9 @@
 
 //  Display the course home page.
 
-    require_once("../config.php");
-    require_once("lib.php");
-    require_once("$CFG->libdir/blocklib.php");
+    require_once('../config.php');
+    require_once('lib.php');
+    require_once($CFG->libdir.'/blocklib.php');
 
     optional_variable($id);
     optional_variable($name);
@@ -25,7 +25,7 @@
 
     require_login($course->id);
 
-    require_once('../calendar/lib.php');    /// This is after login because it needs $USER
+    require_once($CFG->dirroot.'/calendar/lib.php');    /// This is after login because it needs $USER
 
     add_to_log($course->id, "course", "view", "view.php?id=$course->id", "$course->id");