includes/commerce_mailchimp.checkout_pane.inc | 24 +++++++++++++++++-------
 1 file changed, 17 insertions(+), 7 deletions(-)

diff --git a/includes/commerce_mailchimp.checkout_pane.inc b/includes/commerce_mailchimp.checkout_pane.inc
index 0cb5fbe..f9ac625 100644
--- a/includes/commerce_mailchimp.checkout_pane.inc
+++ b/includes/commerce_mailchimp.checkout_pane.inc
@@ -52,6 +52,13 @@ function commerce_mailchimp_pane_settings_form($checkout_pane) {
     );
   }
 
+  if (empty($form)) {
+    // No settings could be displayed because no MailChimp list was configured.
+    $form["commerce_mailchimp_no_list"]['#markup'] = t('<p>No settings could be displayed for this pane because <em>no MailChimp list was configured</em>. Please <a href="!mc_link">create a MailChimp list</a> first before configuring this pane.</p>', array('!mc_link' => url('admin/config/services/mailchimp/lists')));
+    // Show a clearly visible warning message to users.
+    drupal_set_message(t('This checkout pane will not be displayed until you have <a href="!mc_link">configured a MailChimp list</a>.', array('!mc_link' => url('admin/config/services/mailchimp/lists'))), 'warning');
+  }
+
   return $form;
 }
 
@@ -85,13 +92,16 @@ function commerce_mailchimp_pane_checkout_form($form, &$form_state, $checkout_pa
  * Checkout pane callback: validates a MailChimp edit form.
  */
 function commerce_mailchimp_pane_checkout_form_validate($form, &$form_state, $checkout_pane, $order) {
-  $lists = mailchimp_lists_load_multiple_by_name();
-  foreach ($form_state['values']['commerce_mailchimp'] as $name => $value) {
-    $list = $lists[$name];
-    $force = variable_get("commerce_mailchimp_{$list->mc_list_id}_checkout_pane_toggled_disabled",0);
-    if ($force && !$value) {
-      form_set_error('', t("To be able to send important product updates we need your permission to email you. Please check the email subscription box below to give us that permission."));
-      return FALSE;
+  if (!empty($form_state['values']['commerce_mailchimp'])) {
+    $lists = mailchimp_lists_load_multiple_by_name();
+
+    foreach ($form_state['values']['commerce_mailchimp'] as $name => $value) {
+      $list = $lists[$name];
+      $force = variable_get("commerce_mailchimp_{$list->mc_list_id}_checkout_pane_toggled_disabled",0);
+      if ($force && !$value) {
+        form_set_error('', t("To be able to send important product updates we need your permission to email you. Please check the email subscription box below to give us that permission."));
+        return FALSE;
+      }
     }
   }