diff --git a/mod/forum/db/mysql.php b/mod/forum/db/mysql.php
index 821b4a364fc..cfb65ee4b52 100644
--- a/mod/forum/db/mysql.php
+++ b/mod/forum/db/mysql.php
@@ -255,6 +255,7 @@ function forum_upgrade($oldversion) {
           }
           // We need to rebuild all the course caches to refresh the state of
           // the forum modules.
+          include_once( "$CFG->dirroot/course/lib.php" );
           rebuild_course_cache();
           
       } // End if.
diff --git a/mod/forum/db/postgres7.php b/mod/forum/db/postgres7.php
index f3f98d9e814..2332bcb8de2 100644
--- a/mod/forum/db/postgres7.php
+++ b/mod/forum/db/postgres7.php
@@ -213,6 +213,7 @@ function forum_upgrade($oldversion) {
           
           // We need to rebuild all the course caches to refresh the state of
           // the forum modules.
+          include_once( "$CFG->dirroot/course/lib.php" );
           rebuild_course_cache();
           
       } // End if.