asterisk users - Oct 2007 - 423 "Interval Too Brief" back from

I am having problems with SIP Registration. There has been an article 
about the issue 
(http://www.asteriskguru.com/archives/asterisk-users-sip-registration-problem-w-sbc-vt96867.html
)  but I am not able to apply the patch.
I am using AsteriskNow beta6.
The message I am having is:

[Oct  1 19:28:54] NOTICE[19102]: chan_sip.c:7247 sip_reg_timeout:    -- 
Registration for 'XXXXXXXX at voip.server' timed out, trying again
(Attempt #2)
    -- parse_srv: SRV mapped to host mgc.voip.server, port 5060
    -- Got SIP response 423 "Interval Too Brief" back from
voip_server_IP
asteriskNow*CLI>


In AsteriskNow beta I was able to apply the patch and I solved the problem.

Any idea?

Thanks,

Nejc