Every 5 seconds vpxoci-error in emagent.trc, ora-25228

Noticed that the following error was popping up in the emagent.trc of a 10.2.04 – Grid Control-agent  on a specific node, every 5 seconds. Annoying, unnecessary: 2007-09-18 12:15:14 Thread-134875 ERROR vpxoci: Error on dequeue from SYS.ALERT_QUE: ORA-00604: error occurred at recursive SQL level 1 ORA-06502: PL/SQL: numeric or value error ORA-06512: at line 30 ORA-25228: