asterisk users - Aug 2005 - Problem with voicemail, invalid extension, no error handler

I am trying to create a system as follows:

incoming call --> ivr --> sent to dummy extension 1000 --> redirects
user to ring group 2000 -->  (ring group consists of extension 3000
and 4000) --> no answer --> sends to voicemailbox 1000

I want to do this to be able to have one extension number (and
mailbox) for a person but allow them to have multiple extensions
transparently (office, mobile softphone) without having to know more
than 1 single extension.

I have it setup to the point that I have created the voicemail box and
the incoming call gets directed to it but I then get the error:
Aug 10 10:40:48 DEBUG[1906]: Exiting with DIALSTATUS=NOANSWER.
Aug 10 10:40:48 VERBOSE[1906]:     -- Executing
Goto("IAX2/4444@4444/2", "custom-1000|s|2") in new stack
Aug 10 10:40:48 VERBOSE[1906]:     -- Goto (custom-1000,s,2)
Aug 10 10:40:48 VERBOSE[1906]:     -- Executing
Goto("IAX2/4444@4444/2", "exten-vm|1000@default|1000") in
new stack
Aug 10 10:40:48 VERBOSE[1906]:     -- Goto (exten-vm,1000@default,1000)
Aug 10 10:40:48 WARNING[1906]: Channel 'IAX2/4444@4444/2' sent into
invalid extension '1000@default' in context 'exten-vm', but no
invalid
handler
Aug 10 10:40:48 DEBUG[1906]: cdr_mysql: inserting a CDR record.
Aug 10 10:40:48 DEBUG[1906]: cdr_mysql: SQL command as follows: 
INSERT INTO cdr
(calldate,clid,src,dst,dcontext,channel,dstchannel,lastapp,lastdata,duration,billsec,disposition,amaflags,accountcode)
VALUES ('2005-08-10 10:40:37','\"Tim Porritt\"
<4444>','4444','1000@default','exten-vm',
'IAX2/4444@4444/2','IAX2/4445/5','Goto','exten-vm|1000@default|1000',11,0,'NO
ANSWER',3,'')
Aug 10 10:40:48 DEBUG[1906]: We're hanging up IAX2/4444@4444/2 now...
Aug 10 10:40:48 VERBOSE[1906]:     -- Hungup 'IAX2/4444@4444/2'

# this is the error message specifically
Channel 'IAX2/4444@4444/2' sent into invalid extension
'1000@default'
in context 'exten-vm', but no invalid handler

Here is my voicemail.conf entry:
[default]
1000 => 1234,Tim
P,user@email.com,,attach=yes|saycid=no|envelope=no|delete=no|nextaftercmd=no

Not sure what else needs to be done to fix this, any ideas?
Thanks,
Tim