Index: rules.export.inc
===================================================================
--- rules.export.inc	(revision 71)
+++ rules.export.inc	(working copy)
@@ -93,7 +93,7 @@
 /**
  * Implementation of hook_features_export_render() for categories.
  */
-function rules_categories_features_export_render($module = 'foo', $data, $features_export) {
+function rules_categories_features_export_render($module = 'foo', $data, $features_export = '') {
   $code = array();
   $code[] = '  $rules = array();';
   $code[] = '';