--- civicrm_theme.module
+++ (clipboard)
@@ -25,7 +25,7 @@
   return array();
 }
 
-function civicrm_form_alter(&$form, $form_state, $form_id) {
+function civicrm_theme_form_alter(&$form, $form_state, $form_id) {
   if ($form_id == 'system_admin_theme_settings') {
     $newform['civicrm_admin_theme'] = array(
       '#type' => 'select',