=== modified file 'conditional_fields.module'
--- conditional_fields.module	2010-12-01 15:01:41 +0000
+++ conditional_fields.module	2010-12-01 15:02:41 +0000
@@ -309,6 +309,9 @@
     case 'content_copy_import_form':
       $form['#submit'][] = 'conditional_fields_import';
       break;
+    case 'user_register':
+      $form['#after_build'][] = 'conditional_fields_node_after_build';
+      break;
   }
 
   if (isset($form['type']['#value']) && $form_id == $form['type']['#value'] . '_node_form') {
@@ -966,7 +969,7 @@
         else {
           // Do not submit values of controlled fields which were not triggered (except on preview)
           if (variable_get('c_fields_reset_default_' . $form['type']['#value'], 1) &&
-            !in_array('node_form_build_preview', $form_state['submit_handlers'])) {
+            !in_array('node_form_build_preview', (array)$form_state['submit_handlers'])) {
               // Load default values like in content_field_form() in content.node_form.inc
               $field_in_group_info = $form['#field_info'][$field_in_group];
               if (content_callback('widget', 'default value', $field_in_group_info) != CONTENT_CALLBACK_NONE) {