Ive got the same problem on SuSe 11.4 my system freezes and I cant login or ftp in without a hard re-boot (switch off) and on all occasions AVAHI-DAEMON is the last process running:
Nov 10 15:43:41 avahi-daemon: last message repeated 2 times
Nov 10 15:43:41 jscosysv avahi-daemon: Received response from host 192.168.1.220 with invalid source port 49559 on interface 'eth1.0'
Nov 10 15:44:58 avahi-daemon: last message repeated 4 times
Nov 10 16:22:47 jscosysv acpid: 1 client rule loaded
Nov 11 09:31:25 jscosysv kernel: imklog 5.6.5, log source = /proc/kmsg started. (After hard re-boot)
So I have disabled AVAHI hopefully this will cure the problem. John Proctor Lecturer in computing at Tresham College