/var/log/cups/error_log is filled with an error repeated EVERY 5 seconds.
I have no printer on my system, so I can imagine cups can't find any. But there's no reason to make such a fuss about it ;-)
I [29/Mar/2006:01:51:12 +0200] Listening to :631 (IPv4)
I [29/Mar/2006:01:51:12 +0200] Listening to (Domain)
I [29/Mar/2006:01:51:12 +0200] Loaded configuration file "/etc/cups/cupsd.conf"
I [29/Mar/2006:01:51:12 +0200] Cleaning out old temporary files in "/var/spool/cups/tmp"...
I [29/Mar/2006:01:51:12 +0200] Configured for up to 100 clients.
I [29/Mar/2006:01:51:12 +0200] Allowing up to 100 client connections per host.
I [29/Mar/2006:01:51:12 +0200] Using policy "default" as the default!
I [29/Mar/2006:01:51:12 +0200] Full reload is required.
I [29/Mar/2006:01:51:12 +0200] Loaded MIME database from '/etc/cups': 32 types, 39 filters...
E [29/Mar/2006:01:51:12 +0200] cupsdLoadAllPrinters: Unable to open /etc/cups/printers.conf - No such file or directory
E [29/Mar/2006:01:51:12 +0200] cupsdLoadAllClasses: Unable to open /etc/cups/classes.conf - No such file or directory
E [29/Mar/2006:01:51:12 +0200] LoadAllSubscriptions: Unable to open /etc/cups/subscriptions.conf - No such file or directory
I [29/Mar/2006:01:51:12 +0200] Full reload complete.
I [29/Mar/2006:01:51:12 +0200] cupsdStartListening: Listening to 127.0.0.1:631 on fd 0...
I [29/Mar/2006:01:51:12 +0200] cupsdStartListening: Listening to /var/run/cups/cups.sock on fd 1...
E [29/Mar/2006:01:51:13 +0200] CUPS-Get-Default client-error-not-found: No default printer
E [29/Mar/2006:01:51:13 +0200] CUPS-Get-Printers client-error-not-found: No destinations added.
E [29/Mar/2006:01:51:18 +0200] CUPS-Get-Default client-error-not-found: No default printer
E [29/Mar/2006:01:51:18 +0200] CUPS-Get-Printers client-error-not-found: No destinations added.
E [29/Mar/2006:01:51:20 +0200] CUPS-Get-Printers client-error-not-found: No destinations added.
E [29/Mar/2006:01:51:20 +0200] CUPS-Get-Classes client-error-not-found: No destinations added.
E [29/Mar/2006:01:51:20 +0200] CUPS-Get-Default client-error-not-found: No default printer
E [29/Mar/2006:01:51:24 +0200] CUPS-Get-Default client-error-not-found: No default printer
E [29/Mar/2006:01:51:24 +0200] CUPS-Get-Printers client-error-not-found: No destinations added.
E [29/Mar/2006:01:51:28 +0200] CUPS-Get-Default client-error-not-found: No default printer
E [29/Mar/2006:01:51:28 +0200] CUPS-Get-Printers client-error-not-found: No destinations added.
E [29/Mar/2006:01:51:33 +0200] CUPS-Get-Default client-error-not-found: No default printer
E [29/Mar/2006:01:51:33 +0200] CUPS-Get-Printers client-error-not-found: No destinations added.
E [29/Mar/2006:01:51:38 +0200] CUPS-Get-Default client-error-not-found: No default printer
E [29/Mar/2006:01:51:38 +0200] CUPS-Get-Printers client-error-not-found: No destinations added.
E [29/Mar/2006:01:51:43 +0200] CUPS-Get-Default client-error-not-found: No default printer
E [29/Mar/2006:01:51:43 +0200] CUPS-Get-Printers client-error-not-found: No destinations added.
E [29/Mar/2006:01:51:48 +0200] CUPS-Get-Default client-error-not-found: No default printer
E [29/Mar/2006:01:51:48 +0200] CUPS-Get-Printers client-error-not-found: No destinations added.
E [29/Mar/2006:01:51:53 +0200] CUPS-Get-Default client-error-not-found: No default printer
E [29/Mar/2006:01:51:53 +0200] CUPS-Get-Printers client-error-not-found: No destinations added.
in other news:
syslog:Mar 29 19:51:38 dapperdrake cupsd: Unable to open log file "/var/log/cups/error_log" - Permission denied
syslog:Mar 29 20:17:03 dapperdrake cupsd: Unable to open log file "/var/log/cups/error_log" - Permission denied
syslog:Mar 29 20:48:29 dapperdrake cupsd: Unable to open log file "/var/log/cups/error_log" - Permission denied
user.log shows many more of these. Not nearly as much as cups/error_log, though.
Note: the original reporter indicated the bug was in package 'cups'; however, that package was not published in Ubuntu.
Thanks for the bug report. This particular bug has already been reported into our bug tracking system, but please feel free to report any further bugs you find.