Index: wp-includes/post.php
===================================================================
--- wp-includes/post.php	(revision 11588)
+++ wp-includes/post.php	(working copy)
@@ -1759,7 +1759,7 @@
 	} elseif ( in_array($post_type, $hierarchical_post_types) ) {
 		// Page slugs must be unique within their own trees.  Pages are in a
 		// separate namespace than posts so page slugs are allowed to overlap post slugs.
-		$check_sql = "SELECT post_name FROM $wpdb->posts WHERE post_name = %s AND post_type IN ( '" . implode("', '", $wpdb->escape($hierarchical_post_types)) . "' ) AND ID != %d AND post_parent = %d LIMIT 1";
+		$check_sql = "SELECT post_name FROM $wpdb->posts WHERE post_name = %s AND post_type IN ( '" . implode("', '", array_map(array(&$wpdb, 'escape'), $hierarchical_post_types)) . "' ) AND ID != %d AND post_parent = %d LIMIT 1";
 		$post_name_check = $wpdb->get_var($wpdb->prepare($check_sql, $slug, $post_ID, $post_parent));
 		
 		if ( $post_name_check || in_array($slug, $wp_rewrite->feeds) ) {