Its nat.  

notice the 401 
Via: SIP/2.0/UDP 192.168.1.2:5080:5080;rport=14802;branch=z9hG4bKjS09v88N9p59K

IT says I received you from 192.168.1.2:5080 but port 14802 so go fix your nat and fix your external profile with the right info/ip's in it.

/b
Sent from my hospital bed 
On Feb 26, 2012, at 8:14 PM, Vitalie Colosov wrote:

Maybe some explanation can be received from these lines:

    nta: received 401 Unauthorized for REGISTER (24810914)
    nta: 401 Unauthorized has fatal syntax errors
    nta: timer E fired, retransmit REGISTER (24810914)

Curious what are those "syntax errors" which other soft phones are able to overcome...
Maybe it does not like this message?

Warning: 392 217.9.36.145:5060 "Noisy feedback tells:  pid=868 req_src_ip=122.176.168.104 req_src_port=14802 in_uri=sip:sip.iptel.org;transport=udp out_uri=sip:sip.iptel.org;transport=udp via_cnt==1"