diff --git a/mailsystem.theme.inc b/mailsystem.theme.inc
index 8c574ad..070effb 100644
--- a/mailsystem.theme.inc
+++ b/mailsystem.theme.inc
@@ -55,9 +55,9 @@ function mailsystem_theme_theme_registry_alter(&$theme_registry) {
         foreach ($theme_registry as $name => $hook) {
           if (!empty($hook['mail theme'])) {
             if (isset($cache[$name])) {
-              $cache[$name]['includes'][] = drupal_get_path('theme', $theme->name) . '/template.php';
+              $cache[$name]['include files'][] = drupal_get_path('theme', $theme->name) . '/template.php';
               foreach ($base_theme as $base) {
-                $cache[$name]['includes'][] = drupal_get_path('theme', $base->name) . '/template.php';
+                $cache[$name]['include files'][] = drupal_get_path('theme', $base->name) . '/template.php';
               }
               // Change the current registry for the new record.
               $theme_registry[$name] = $cache[$name];
@@ -66,9 +66,9 @@ function mailsystem_theme_theme_registry_alter(&$theme_registry) {
             // Look for template suggestions.
             foreach ($cache as $cache_name => $cache_hook) {
               if (strpos($cache_name, $name . '__') !== FALSE) {
-                $cache_hook['includes'][] = drupal_get_path('theme', $theme->name) . '/template.php';
+                $cache_hook['include files'][] = drupal_get_path('theme', $theme->name) . '/template.php';
                 foreach ($base_theme as $base) {
-                  $cache_hook['includes'][] = drupal_get_path('theme', $base->name) . '/template.php';
+                  $cache_hook['include files'][] = drupal_get_path('theme', $base->name) . '/template.php';
                 }
                 // Change the current registry for the new record.
                 $theme_registry[$cache_name] = $cache_hook;