diff --git a/booking.variety_admin.inc b/booking.variety_admin.inc
index 2ed34d9..743ef70 100644
--- a/booking.variety_admin.inc
+++ b/booking.variety_admin.inc
@@ -861,16 +861,18 @@ function booking_variety_regn_edit_form_submit($form, &$form_state) {
     }
 
     //iterate over the old list comparing to the new list in case there are regn counts we need to decrease
-    foreach ($previous_variety_ids as $previous_tid => $previous_sid) {
-      if (! isset($booking_variety_ids[$previous_tid])) {
-        watchdog('booking_debug', 'Person @nid in timeslot @tid is no longer registered for a variety session so reducing count for @vid by 1', array(
-          '@nid' => $values['nid'], '@tid' => $previous_tid, '@vid' => $previous_sid,
-        ));
-        // reduce regn count for old session
-        db_update('booking_variety_sessions')
-          ->expression('booking_variety_regncount', 'booking_variety_regncount - :count', array(':count' => 1))
-          ->condition('vid', $previous_sid)
-          ->execute();          
+    if (isset($previous_variety_ids)) {
+      foreach ($previous_variety_ids as $previous_tid => $previous_sid) {
+        if (! isset($booking_variety_ids[$previous_tid])) {
+          watchdog('booking_debug', 'Person @nid in timeslot @tid is no longer registered for a variety session so reducing count for @vid by 1', array(
+            '@nid' => $values['nid'], '@tid' => $previous_tid, '@vid' => $previous_sid,
+          ));
+          // reduce regn count for old session
+          db_update('booking_variety_sessions')
+            ->expression('booking_variety_regncount', 'booking_variety_regncount - :count', array(':count' => 1))
+            ->condition('vid', $previous_sid)
+            ->execute();          
+        }
       }
     }