Why it is always unregisted?

i am very confused. my asteisk server version is 1.0.9
the following is the content of my iax.conf:
[general]
bindport = 4569 ; Port to bind to (IAX is 4569)
bindaddr = 0.0.0.0 ; Address to bind to (all addresses on machine)
disallow=all
allow=ilbc

mailboxdetail=yes
dbname=asterisk
dbhost=localhost
dbuser=user
dbpass=mypass
#include iax_additional.conf
#include iax_custom.conf

i also open the mysql_friend in the makefile of channel directory .
and remake them all.
i have a iaxclient.i insert some data into iaxfriends table in database asterisk.e.g. username : 123456 password:123 context :mycontext
username: 123457 password:123 context:mycontext.
finish these steps i can use my iaxclients to login and call each other.but asterisk server hint that unregister"123456" .what 's wrong?