Index: modules/book/book.admin.inc
===================================================================
RCS file: /cvs/drupal/drupal/modules/book/book.admin.inc,v
retrieving revision 1.8.2.2
diff -u -p -r1.8.2.2 book.admin.inc
--- modules/book/book.admin.inc	8 Jul 2008 10:19:46 -0000	1.8.2.2
+++ modules/book/book.admin.inc	15 Oct 2008 17:30:42 -0000
@@ -170,8 +170,8 @@ function _book_admin_table($node, &$form
  * @see book_admin_edit()
  */
 function _book_admin_table_tree($tree, &$form) {
-  foreach ($tree as $key => $data) {
-    $form[$key] = array(
+  foreach ($tree as $data) {
+    $form['book-admin-'. $data['link']['nid']] = array(
       '#item' => $data['link'],
       'nid' => array('#type' => 'value', '#value' => $data['link']['nid']),
       'depth' => array('#type' => 'value', '#value' => $data['link']['depth']),