Zabbix trigger check if string exists in amount of time

[sanderm]

Hi,

I have a problem with my Trigger in Zabbix.

I Want to trigger an alert if a windows event log does not contains an event in 24 hours.
I tried

{Backup Exec 2010:eventlog[Application,,,,34112,,].str("Daily Full Backup",86400)}=0

But it is not working. What am I doing wrong here?