asterisk users - Mar 2005 - Error cant change devie with no technology

Guys.

What does this error mean?

    -- Playing '/var/spool/asterisk/voicemail/intruder/201/unavail'
(language 'sp')
    -- Playing 'vm-intro' (language 'sp')
    -- Playing 'beep' (language 'sp')
    -- Recording the message
    -- x=0, open writing:
/var/spool/asterisk/voicemail/intruder/201/INBOX/msg0000 format: wav,
0x812b4f0
    -- User ended message by pressing #
    -- Playing 'auth-thankyou' (language 'sp')
    -- Playing 'vm-review' (language 'sp')
    -- Saving message as is
    -- Playing 'vm-msgsaved' (language 'sp')
Mar 11 20:40:27 WARNING[3438]: app_queue.c:374 changethread: Can't change
device '**Unknown**' with no technology!
Mar 11 20:40:27 WARNING[3438]: app_queue.c:374 changethread: Can't change
device '**Unknown**' with no technology!
Mar 11 20:40:27 WARNING[3438]: app_queue.c:374 changethread: Can't change
device '**Unknown**' with no technology!
    -- Executing Playback("Zap/2-1", "vm-goodbye") in new
stack
    -- Playing 'vm-goodbye' (language 'sp')
    -- Executing Hangup("Zap/2-1", "") in new stack
  == Spawn extension (macro-stdexten, s-NOANSWER, 3) exited non-zero on
'Zap/2-1' in macro 'stdexten'
  == Spawn extension (intruder, 201, 2) exited non-zero on 'Zap/2-1'
    -- Hungup 'Zap/2-1'

I havent been able to figure out what does this error mean? Voicemails works
fine but I am wondering..

Any pointers?