Problem: "Notice: Undefined index: boost_domain_whitelist_use_domain in boost_admin_boost_performance_page_submit() boost.admin.inc."

Fix: Edit boost.admin.inc

    //split white/blacklists into arrays
    $whitelist_values = explode("\n", $form_state['values']['boost_domain_whitelist']);
    $whitelist_values = array_map('trim', $whitelist_values);
    $whitelist = array_combine($whitelist_values, $whitelist_values);
-    if ($form_state['values']['boost_domain_whitelist_use_domain'] && function_exists('domain_domains')) {
+    if (!empty($form_state['values']['boost_domain_whitelist_use_domain']) && function_exists('domain_domains')) {
      $extra_domains = domain_domains();
      foreach ($extra_domains as $key => $extra_domain) {
        $whitelist[ $extra_domain['subdomain'] ] = $extra_domain['subdomain'];
      }
    }
    asort($whitelist);