Oracle Database Discussions

Hi,

I have Oracle 10 G installed on Windows Server 2003.Frequently I am getting End -Of-Communication Channel error.
If i restart the Database then it is working fine but it is repeated after few days.
In my alert log I found the following

Tue Aug 10 14:50:58 2010
Errors in file c:\oradata\litelocn\udump\litelocn_ora_1704.trc:
ORA-07445: exception encountered: core dump [ACCESS_VIOLATION] [_opidsa+360] [PC:0x214FC78] [ADDR:0x0] [UNABLE_TO_READ] []

Udump

ORA-07445: exception encountered: core dump [ACCESS_VIOLATION[_opidsa+360] [PC:0x214FC78] [ADDR:0x0] [UNABLE_TO_READ] []
Current SQL statement for this session:
select object_name, owner object_owner, status, object_type, created, last_ddl_time
from sys.all_objects
where object_type = :object_type
and (owner = user)
order by decode(owner, user, 0, 1),
owner,
object_name


Can you Please suggest me what is the cause for this
Thanks.