diff --git a/calendar/inc/class.calendar_ical.inc.php b/calendar/inc/class.calendar_ical.inc.php
index 09ec8aaff1..6d3e339ab2 100644
--- a/calendar/inc/class.calendar_ical.inc.php
+++ b/calendar/inc/class.calendar_ical.inc.php
@@ -825,7 +825,7 @@ class calendar_ical extends calendar_boupdate
  								continue;	// participants without email AND CN --> ignore it
  							}
 							elseif ((list($data) = ExecMethod2('addressbook.addressbook_bo.search',$searcharray,
-								'id,account_id,n_fn','account_id IS NOT NULL DESC, n_fn IS NOT NULL DESC','','',false,'OR')))
+								array('id','account_id','n_fn'),'account_id IS NOT NULL DESC, n_fn IS NOT NULL DESC','','',false,'OR')))
 							{
 								$uid = $data['account_id'] ? (int)$data['account_id'] : 'c'.$data['id'];
 							}