diff --git skinr.module skinr.module
index 408cc5c..56ecb71 100644
--- skinr.module
+++ skinr.module
@@ -306,8 +306,12 @@ function skinr_preprocess(&$vars, $hook) {
   $current_theme = skinr_current_theme();
   $theme_registry = theme_get_registry();
 
+
+  $themes = array();
   // Add any base themes.
-  $themes = array_keys(system_find_base_themes(_system_theme_data(), $current_theme));
+  if (!empty($themes[$current_theme]->info['base theme'])) {
+    $themes = array_keys(system_find_base_themes(_system_theme_data(), $current_theme));
+  }
   // Add the current theme.
   $themes[] = $current_theme;