Problem with Codec G729

Hello,

I have problem with codec g729

if the configuration in sip.conf is :
[general]
;disallow=all
;allow=gsm
;allow=ulaw
;allow=alaw
;allow=ilbc
;allow=g729

my-codecs ; a template for my preferred codecs
disallow=all
allow=g729
allow=gsm
allow=ulaw
allow=g723
allow=ilbc

All calls of codec g729 are rejected
[Sep 28 13:01:18] NOTICE[27143]: chan_sip.c:9373 process_sdp: No compatible codecs, not accepting this offer!

if the configuration is :
[general]
;disallow=all
;allow=gsm
;allow=ulaw
;allow=alaw
;allow=ilbc
allow=g729

the calls are passed with warning
translate.c:439 ast_translator_build_path: No translator path from g729 to slin
and a lot of warnings filling the cli

and the server is stop working after some hours, sometimes the process stopped and sometimes it stop processing calls so we need to restart.

I am using
Asterisk 10.2.1 built by root @ CentOS-58-64-minimal on a x86_64 running Linux on 2012-03-29 22:32:00 UTC

and I have installed G729 codec
0/0 encoders/decoders of 30 licensed channels are currently in use

the counter of encoders or decoders is changing sometimes but with no sense because I don’t know which one use codec or not

So, what is the real problem here and how can I solve it.