Server hang on after few hours continuously

hi, everyone,
i have been sufferred for the asterisk hang on problem for so long and i just reinstalled the whole thing yesterday, but again this morning the server hangs on again, you could not call in through PSTN line and the ppl also could not call out throught the server, there is simply engaged dial tone when you try to do so. and the only thing i can do is to restart asterisk server after some hours or one day. i am using asterisk 1.2.17 + zaptel 1.2.16 + freepbx 2.2.1.

[root@pt3 ~]# tail /var/log/asterisk/full
Apr 5 09:38:17 DEBUG[6351] manager.c: Manager received command 'Command’
Apr 5 09:38:17 DEBUG[6351] manager.c: Manager received command 'Command’
Apr 5 09:38:17 DEBUG[6351] manager.c: Manager received command 'Command’
Apr 5 09:38:31 DEBUG[6305] chan_sip.c: Stopping retransmission on '293c2fcd70fb

8aaa03446f167fabe7e1@192.168.0.102
’ of Request 102: Match Found
Apr 5 09:38:32 DEBUG[6299] chan_iax2.c: Peer lastms 286, historicms 286, maxms 2000
Apr 5 09:38:34 VERBOSE[6262] logger.c: – Remote UNIX connection
Apr 5 09:38:34 VERBOSE[8867] logger.c: – Remote UNIX connection disconnect ed
Apr 5 09:38:35 DEBUG[6305] chan_sip.c: Stopping retransmission on '777d42677b83

50b42ba306cb78cc7f80@192.168.0.102
’ of Request 102: Match Found
Apr 5 09:38:37 DEBUG[6305] chan_sip.c: Stopping retransmission on '03d3c07e09b3

b81c2eb122256223db48@192.168.0.102
’ of Request 102: Match Found
Apr 5 09:38:37 DEBUG[6305] chan_sip.c: Stopping retransmission on '525fcce86064

Any one please give me some advice on this? thanks so much really,

what is the “hang on” problem ? is it just Asterisk that’s affected ? DNS issues ? loss of 'net connection ? other logs ?