My database is shutting down frequently (once in 24 hours)

Please see the below Alert file and trace file and suggest me what should I do


Alert file
=========
Mon May 04 11:44:05 2009
Process q002 started up but failed with error = 20
Process q002 started up but failed with error = 20
Process q002 started up but failed with error = 20
Process q002 started up but failed with error = 20
Process q002 started up but failed with error = 20
Mon May 04 11:49:18 2009
Process q005 started up but failed with error = 20
Process q005 started up but failed with error = 20
Process q005 started up but failed with error = 20
Process q005 started up but failed with error = 20
Process q005 started up but failed with error = 20
Mon May 04 11:51:02 2009
Private_strands 7 at log switch
Thread 1 advanced to log sequence 44692
Current log# 3 seq# 44692 mem# 0: D:\ORACLE\PRODUCT\10.1.0\ORADATA\ORCLJDE\REDO03.LOG
Mon May 04 11:52:31 2009
Errors in file d:\oracle\product\10.1.0\admin\orcljde\udump\orcljde_ora_3800.trc:
ORA-25254: time-out in LISTEN while waiting for a message
ORA-06512: at “SYS.DBMS_AQ”, line 577
ORA-06512: at “SYSMAN.EMD_NOTIFICATION”, line 492
ORA-06512: at line 1
————————————————————————————————

When I checked individual trace file it shows as below
=====================================

Dump file d:\oracle\product\10.1.0\admin\orcljde\bdump\orcljde_ora_4392.trc
Mon May 04 11:02:28 2009
ORACLE V10.1.0.2.0 - Production vsnsta=0
vsnsql=13 vsnxtr=3
Oracle Database 10g Enterprise Edition Release 10.1.0.2.0 - Production
With the Partitioning, OLAP and Data Mining options
Windows Server 2003 Version V5.2 Service Pack 2
CPU : 4 - type 586, 2 Physical Cores
Process Affinity: 0Χ00000000
Memory (A/P) : PH:20392M/24575M, PG:27290M/32151M, VA:940M/2047M
Instance name: orcljde

Redo thread mounted by this instance: 1

Oracle process number: 0

4392

Died during process startup with error 20 (seq=1464)
OPIRIP: Uncaught error 20. Error stack:
ORA-00020: maximum number of processes (150) exceeded


Plz help me