intermittent TNS-12533: TNS:illegal ADDRESS parameters I am running a windows XP (SP3) VM in virtualbox, on which I host Oracle XE.

It has been running fine like this for a couple of years, but recently I am seeing some strange problems.

My client software fails, and the log files say :
ORA-12505, TNS:listener does not currently know of SID given in connect descriptor

So I log on to the DB, and try running sqlplus / as sysdba;

which gives me the following:
ora-12560 tns protocol adapter error

So following the debugging steps from several websites, I try this:
tnsping db
and the result is :
TNS-12533: TNS:illegal ADDRESS parameters

So I decide to test another SID:
tnsping xe
which works fine.  

As you can see from the tnsnames.ora file, those two SIDs are configured identically.

I've not touched that file in a couple of years and don't intend to do so now.

So I restart the windows machine, and now everything works.

Why did the error message indicate a problem with the file, when upon restart it doesn't complain?

Why would this suddenly stop working?

I checked the alert log and found this:

ORA-27300: OS system dependent operation:CreateThread failed with status: 8
ORA-27301: OS failure message: Not enough storage is available to process this command.
ORA-27302: failure occurred at: ssthrddcr
Process J000 died, see its trace file
kkjcre1p: unable to spawn jobq slave process 


I've tried wiping some files from the hard disk (there was 1GB free space, which seems like plenty) but it hasn't worked.

Any ideas?

The contents of my tnsnames.ora file include:

XE =
  (DESCRIPTION =
  (ADDRESS = (PROTOCOL = TCP)(HOST = windows-virtual)(PORT = 1521))
  (CONNECT_DATA =
    (SERVER = DEDICATED)
    (SERVICE_NAME = XE)
  )
)

DB=
 (DESCRIPTION =
   (ADDRESS = (PROTOCOL = TCP)(HOST = windows-virtual)(PORT = 1521))
   (CONNECT_DATA =
     (SERVER = DEDICATED)
     (SERVICE_NAME = DB)
   )
 )
Try any one or both 


Try using IP for HOST
Also remove (SERVER = DEDICATED) row from tnsname.ora file.