diff --git a/mod/forum/discuss.php b/mod/forum/discuss.php
index 57c5d66b0f4..8c3c0454371 100644
--- a/mod/forum/discuss.php
+++ b/mod/forum/discuss.php
@@ -104,8 +104,8 @@
     }
     
     //check if user can view this post
-    if (!forum_user_can_view_post($parent)){
-        error ('you can not view this post');
+    if (!forum_user_can_view_post($parent,$course)){
+        error('You do not have permissions to view this post');
     }
 
     if (! $post = forum_get_post_full($parent)) {
diff --git a/mod/forum/lib.php b/mod/forum/lib.php
index c2326ab3e24..be776cc0029 100644
--- a/mod/forum/lib.php
+++ b/mod/forum/lib.php
@@ -2658,7 +2658,7 @@ function forum_user_can_post($forum, $user=NULL) {
 }
 
 //checks to see if a user can view a particular post
-function forum_user_can_view_post($post, $user=NULL){
+function forum_user_can_view_post($post, $course, $user=NULL){
 
     global $CFG, $USER;
 
@@ -2684,7 +2684,9 @@ function forum_user_can_view_post($post, $user=NULL){
     }
 
     //first of all, the user must be in this course
-    if (!(isstudent($forumcourse->course) or isteacher($forumcourse->course))){
+    if (!(isstudent($forumcourse->course) or 
+          isteacher($forumcourse->course) or 
+          (isguest() && $course->guest) )){
         return false;
     }