Hi Fajar, I Couldn't solve the problem yet... but I ran the Radius in debug mode, and I tried to disconnect my connection to see what are happening, as I couldn't find, I'll post it here. 

Thanks for the help.

rad_recv: Accounting-Request packet from host XXX.XX.X.XXX:37121, id=232, length=268
        Service-Type = Framed-User
        Framed-Protocol = PPP
        NAS-Port = 115296
        NAS-Port-Type = Ethernet
        User-Name = "email@domain.com.br"
        Calling-Station-Id = "00:15:6D:E6:94:DB"
        Called-Station-Id = "pppoe-wip2"
        NAS-Port-Id = "WIP2"
        MS-CHAP-Domain = "domain.com.br"
        Acct-Session-Id = "81514b64"
        Framed-IP-Address = xxx.xx.X.XX
        Acct-Authentic = RADIUS
        Event-Timestamp = "Feb 17 2012 13:44:23 BRST"
        Acct-Session-Time = 79376
        Acct-Input-Octets = 158226957
        Acct-Input-Gigawords = 0
        Acct-Input-Packets = 1112930
        Acct-Output-Octets = 854637707
        Acct-Output-Gigawords = 0
        Acct-Output-Packets = 1115931
        Acct-Status-Type = Stop
        Acct-Terminate-Cause = NAS-Request
        NAS-Identifier = "PPPoE-AND WIP2"
        Acct-Delay-Time = 0
        Mikrotik-Realm = "domain.com.br"
        NAS-IP-Address = xxx.xx.x.xx
Processing the preacct section of radiusd.conf
modcall: entering group preacct for request 43
  modcall[preacct]: module "preprocess" returns noop for request 43
rlm_acct_unique: Hashing 'NAS-Port = 115296,Client-IP-Address = xxx.xx.x.xx,NAS-IP-Address = xxx.xx.x.xxx,Acct-Session-Id = "81514b64",User-Name = "email@domain.com.br"'
rlm_acct_unique: Acct-Unique-Session-ID = "4bc00ddcf558a324".
  modcall[preacct]: module "acct_unique" returns ok for request 43
    rlm_realm: Looking up realm "domain.com.br" for User-Name = "email@domain.com.br"
    rlm_realm: No such realm "domain.com.br"
  modcall[preacct]: module "suffix" returns noop for request 43
  modcall[preacct]: module "files" returns noop for request 43
modcall: leaving group preacct (returns ok) for request 43
  Processing the accounting section of radiusd.conf
modcall: entering group accounting for request 43
radius_xlat:  '/var/log/radacct/xxx.xx.x.xx/detail-20120217'
rlm_detail: /var/log/radacct/%{Client-IP-Address}/detail-%Y%m%d expands to /var/log/radacct/xxx.xx.x.xx/detail-20120217
  modcall[accounting]: module "detail" returns ok for request 43
  modcall[accounting]: module "unix" returns fail for request 43
modcall: leaving group accounting (returns fail) for request 43
Finished request 43
Going to the next request


And the sqltrace, the only information with acct-stop-time is this:

UPDATE
    radacct
SET
    AcctStopTime='2012-02-10 17:43:19',
    AcctSessionTime=unix_timestamp('2012-02-10 17:43:19') - unix_timestamp(AcctStartTime),
    AcctTerminateCause='',
    AcctStopDelay = '0'
WHERE
    AcctSessionTime=0
AND
    AcctStopTime=0
AND
    NASIPAddress= 'xxx.xx.x.xx'
AND
    AcctStartTime <= '2012-02-10 17:43:19';


both were not collected from the same time.




De: Fajar A. Nugraha <list@fajar.net>
Para: Rodrigo Yoshioka <ro_yoshioka2002@yahoo.com.br>; FreeRadius users mailing list <freeradius-users@lists.freeradius.org>
Enviadas: Terįa-feira, 7 de Fevereiro de 2012 14:00
Assunto: Re: Freeradius doesn't record acct-stop-time.

On Tue, Feb 7, 2012 at 10:48 PM, Rodrigo Yoshioka
<ro_yoshioka2002@yahoo.com.br> wrote:
> Hi...
>
> My freeradius are recording in mysql all sessions about start connection,
> but it didnīt finish it. when a device is logged out it remain connected at
> mysql, doing my proprietary CRM mistake to return connection data.
>
> Checking detailed log, its registering start connection and stop connection,
> the problem is just in mysql... It is probably a configuration that I should
> enable, but I donīt know wich. Can anyone help me.?

Did it suddenly stopped working, or did it never worked at all?

Enabling sql in accounting section should handle accounting packets.
If you're having problems, running it in debug mode (or enabling
sqltrace) might help you find out what queries are being executed, and
why they fail (if that's indeed the cause).

--
Fajar