asterisk users - May 2004 - SIP 404 error....

I've buyed SIP traffic from platinumcalling.com.au.

in sip.conf i have:

[platinum]
context=default
type=peer
username=MYUSERNAME
secret=MYPASSWORD
host=sip.platinumcalling.com.au

in my extension.conf:

[default]
exten => _XXXXX.,1,Dial,SIP/${EXTEN}@platinum|60|r

When i try to call a number i got:

Got SIP response 404 "Not Found" back from 203.30.19.164
SIP/platinum-67f2 is circuit-busy

What's the problem ???

Thanks,
Igor