Oracle Database Discussions

Hi,

I have a problem on an Oracle Database 10g Enterprise Edition Release 10.1.0.2.0 on Windows Server 2003.
In mmon*.trc I found many messages like

*** KEWRAFC: Flush slave failed, return Code: 5.

and some hours later:

*** KEWROCISTMTEXEC - encountered error: (ORA-00604: error occurred at recursive SQL level 3
ORA-04021: timeout occurred while waiting to lock object
)
*** SQLSTR: total-len=1293, dump-len=240,
STR={INSERT /*+ APPEND */ INTO WRH$_ACTIVE_SESSION_HISTORY ( snap_id, dbid, instance_number, sample_id, sample_time, session_id, session_serial#, user_id, sql_id, sql_child_number, sql_plan_hash_value, service_hash, session_type, sql}
kewa_flusher: Exception handler 13509 - Will resignal!
kewa_eflush_cb: Exception handler 13509
kewa_eflush_cb: Cleared error 13509

After this message the database stands and I got every hour a tracefile m001*.trc with this:

*** ACTION NAME:(Auto-DBFUS Action) 2007-03-02 00:39:05.596
*** MODULE NAME:(MMON_SLAVE) 2007-03-02 00:39:05.596
*** SERVICE NAME:(SYS$BACKGROUND) 2007-03-02 00:39:05.596
*** SESSION ID:(146.136) 2007-03-02 00:39:05.596
*********START PLSQL RUNTIME DUMP************
***Got internal error Exception caught in pfrrun() while running PLSQL***
***Got ORA-604 while running PLSQL***
PACKAGE BODY SYS.DBMS_FEATURE_USAGE_INTERNAL:
...
...
...
***********END PLSQL RUNTIME DUMP************
*** KEWUXS - encountered error: (ORA-00604: error occurred at recursive SQL level 2
ORA-04021: timeout occurred while waiting to lock object
)
*** KEWFADS: Error=13515 encountered by Auto DBFUS slave.

and in mmon*.trc this messages

kwqicaclcur: Error 604
Error(2) 4021
Cursor Session Number : 153
Cursor Session Serial : 2
Cursor Pin Number : 13322

and an corresponding message in the alert.log:

ORA-604 encountered when generating server alert SMG-3503

After restarting the database it seems to be OK.
Anybody know the reason for the problem?
Any help would be appreciated.

Greetings SEH.