SQL & PL/SQL

Hi I want to query the alerts V$DIAG_ALERT_EXT from, but I only want those that are not older than 30 days V$DIAG_ALERT_EXT.

Right now I have:

select to_char(originating_timestamp,'DD.MM.YYYY HH24:MI:SS'), message_text
  from V$DIAG_ALERT_EXT
  where trim(COMPONENT_ID)='rdbms'
  and MESSAGE_TEXT like '%ORA-%'
  or MESSAGE_TEXT like '%TNS-%'
  or MESSAGE_TEXT like '%Checkpoint not%'
  and originating_timestamp < sysdate-interval '30' day
  order by 1;

But this is not working :/