commit 29d3099bb680ce9af960d4888f1d795c54d932d7
Author: David Mudrak <david@moodle.com>
Date:   Fri Jul 1 22:10:21 2011 +0200

    MDL-28152 Improved detection of the course grade_category on course restore

diff --git a/backup/moodle2/restore_stepslib.php b/backup/moodle2/restore_stepslib.php
index 500343d..587ad6e 100644
--- a/backup/moodle2/restore_stepslib.php
+++ b/backup/moodle2/restore_stepslib.php
@@ -236,6 +236,7 @@ class restore_gradebook_structure_step extends restore_structure_step {
             //get the already created course level grade category
             $category = new stdclass();
             $category->courseid = $this->get_courseid();
+            $category->parent = null;
 
             $coursecategory = $DB->get_record('grade_categories', (array)$category);
             if (!empty($coursecategory)) {