diff --git a/CRM/EventsExtras/Form/Settings.php b/CRM/EventsExtras/Form/Settings.php
index 3ce210a..b64f694 100644
--- a/CRM/EventsExtras/Form/Settings.php
+++ b/CRM/EventsExtras/Form/Settings.php
@@ -249,7 +249,8 @@ public function setDefaultValues() {
     }
 
     $defaults['eventsextras_payment_processor_selection_default'] =
-      array_fill_keys($defaults['eventsextras_payment_processor_selection_default'], '1');
+      is_array($defaults['eventsextras_payment_processor_selection_default']) ?
+      array_fill_keys($defaults['eventsextras_payment_processor_selection_default'], '1') : NULL;
 
     return $defaults;
   }