diff --git a/booking.regn_form.inc b/booking.regn_form.inc
index 7dca1b4..0f1b34f 100644
--- a/booking.regn_form.inc
+++ b/booking.regn_form.inc
@@ -1241,7 +1241,7 @@ function booking_form_validate($form, &$form_state) {
     form_set_error('booking_agreement', t('You must read and agree with the aims and expectations prior to submitting this form.'));
   }
 
-  if (variable_get('booking_enable_previous_studyweeks', 0) == 1 && $data['booking_prev_sw_count'] == '') {
+  if (variable_get('booking_require_previous_sw', 0) == 1 && $data['booking_prev_sw_count'] == '') {
     form_set_error('booking_prev_sw_count', t('You must select the number of study weeks that you\'ve previously attended.'));
   }