asterisk users - Jun 2004 - Unable to call other SIP Phone

All,

I am setting up my first * box and am trying to configure SIP Softphone to SIP
softphone dialing.
When I dial ext. 2001 it rings once (Very short) then immediately goes to voice
mail for ext. 2001.
I keep seeing the "Got SIP response 482 "Loop Detected" back from
192.168.1.252", immediately followed
by "No one is available to answer at this time".  

I've searched the archives and found some information on this error, but was
unable to resolve it with the
information.  Has anyone run into this before?

Here is the output from my console:
=======================================================================Urgent
handler
    -- Called tysjphone
Urgent handler
    -- Got SIP response 482 "Loop Detected" back from 192.168.1.252
Urgent handler
  == No one is available to answer at this time
Urgent handler
    -- Playing 'vm-theperson' (language 'en')
Urgent handler
    -- Playing 'digits/2' (language 'en')
Urgent handler
    -- Playing 'digits/0' (language 'en')
Urgent handler
    -- Playing 'digits/0' (language 'en')
Urgent handler
    -- Playing 'digits/1' (language 'en')
Urgent handler
    -- Playing 'vm-isunavail' (language 'en')
Urgent handler
    -- Playing 'vm-intro' (language 'en')
==================================================


Thank you,

Ty Purcell