Comment 28 for bug 444597

correction:
for me the problem is actually twofold: sharing printers via cups over the local network does not work any more since the upgrade from jaunty to karmic but the cups service seems to be running.
sharing printers via samba does not work, because samba complains that it cannot find the cups service:

/var/log/smbamba/log.smbd:
[2009/11/10 19:44:48, 0] smbd/server.c:1068(main)
  smbd version 3.4.0 started.
  Copyright Andrew Tridgell and the Samba Team 1992-2009
[2009/11/10 19:44:48, 0] printing/print_cups.c:103(cups_connect)
  Unable to connect to CUPS server localhost:631 - Connection refused
[2009/11/10 19:44:48, 0] printing/print_cups.c:103(cups_connect)
  Unable to connect to CUPS server localhost:631 - Connection refused
[2009/11/10 19:44:49, 0] smbd/server.c:456(smbd_open_one_socket)
  smbd_open_once_socket: open_socket_in: Address already in use
[2009/11/10 19:44:49, 0] smbd/server.c:456(smbd_open_one_socket)
  smbd_open_once_socket: open_socket_in: Address already in use

if I manually restart samba, printer sharing via samba seems to work.