asterisk users - Apr 2003 - * process stops, after a few hours of uptime

Greetings

It seems after a while, the asterisk process stops.
The only information I could find, were from the /var/log/asterisk/message
file.
Since I am not a programmer, I have not idea what this could be.

I am thinking it maybe related in registering to another SIP server (PCH or
FWD).

I have commented them out in my sip.conf for now. To see if that helps any.

Any ideas?

Apr  4 01:58:30 NOTICE[81926]: File chan_sip.c, Line 2233
(transmit_register): Scheduled a timeout # 930
Apr  4 01:58:36 WARNING[81926]: File chan_sip.c, Line 358 (retrans_pkt):
Maximum retries exceeded on call 27c58fa6718447624ecdbe836c6fe
8e4@127.0.0.1 for seqno 236 (Request)
Apr  4 01:58:40 NOTICE[81926]: File chan_sip.c, Line 2191 (sip_reg_timeout):
Registration timed out, trying again
Apr  4 01:58:40 WARNING[81926]: File chan_sip.c, Line 334 (__sip_xmit):
sip_xmit of 0x80cad0c (len 321) to 0.0.0.0 returned -1: Invalid
 argument
Apr  4 01:58:41 WARNING[81926]: File chan_sip.c, Line 334 (__sip_xmit):
sip_xmit of 0x80cad0c (len 321) to 0.0.0.0 returned -1: Invalid
 argument
Apr  4 01:58:42 WARNING[81926]: File chan_sip.c, Line 334 (__sip_xmit):
sip_xmit of 0x80cad0c (len 321) to 0.0.0.0 returned -1: Invalid
 argument
Apr  4 01:58:43 WARNING[81926]: File chan_sip.c, Line 334 (__sip_xmit):
sip_xmit of 0x80cad0c (len 321) to 0.0.0.0 returned -1: Invalid
 argument
Apr  4 01:58:44 WARNING[81926]: File chan_sip.c, Line 334 (__sip_xmit):
sip_xmit of 0x80cad0c (len 321) to 0.0.0.0 returned -1: Invalid
 argument
Apr  4 01:58:45 WARNING[81926]: File chan_sip.c, Line 334 (__sip_xmit):
sip_xmit of 0x80cad0c (len 321) to 0.0.0.0 returned -1: Invalid
 argument
Apr  4 01:58:46 WARNING[81926]: File chan_sip.c, Line 358 (retrans_pkt):
Maximum retries exceeded on call  for seqno 1 (Request)
Apr  4 01:58:46 WARNING[81926]: File chan_sip.c, Line 739 (__sip_destroy):
(nil) is not in list?!?! 

Thanks in advance.
Frank...