[asterisk-users] Asterisk loosing IAX users's registration??

[asterisk at mazone.info]

Can anyone tell me why my * is loosing the IAX user's registration?

Before, I had asterisk installed with root, and after a hardware failure I
reinstalled it under the user "asterisk"

I'm using exactly the same configuration as before, exactly the same version
as before but now when I try to call any IAX users it fails right the way
and send me to the voicemail, I have to tray 3 or 4 times until asterisk
succeed to contact the user.

lnxca*CLI> core show version
Asterisk 1.4.16.2 built by asterisk @ lnxca
Running on Fedora 7

Any ideas?
Any help will be really appreciated, Thanks in advance!