Print-Job client-error-not-authorized... Ugh!

[Duncan Hudson]

I've been happily printing with cups 1.2x and Fedora 4 2.6.16-1.2115_FC4smp for a very long time.  Yesterday, out of the blue everything fell apart (yes, I'm sure there was a precursor but I have no idea what it was).  If I print from an app's standard menu (eg. file, print) everything still works fine.  If I try to print from our financial application (SQL-Ledger), or a half dozen scripts that run based upon cron jobs (both of which call lpr -Pprintername) they fail.  I have now upgraded to the current stable version of cups, and verified that the problem also exists on our Fedora 6 development box.  With debug set I see the following in access_log when I successfully print (file, print):

localhost - - [04/Oct/2007:08:31:44 -0400] "POST / HTTP/1.1" 200 140 CUPS-Get-Printers successful-ok
localhost - - [04/Oct/2007:08:31:44 -0400] "POST / HTTP/1.1" 200 140 CUPS-Get-Classes successful-ok
localhost - - [04/Oct/2007:08:31:44 -0400] "POST / HTTP/1.1" 200 80 CUPS-Get-Default successful-ok
localhost - - [04/Oct/2007:08:31:44 -0400] "POST /printers/Checks HTTP/1.1" 200 72298 Print-Job successful-ok
localhost - - [04/Oct/2007:08:31:44 -0400] "POST /printers/Checks HTTP/1.1" 200 142 Get-Job-Attributes successful-ok
localhost - - [04/Oct/2007:08:31:44 -0400] "POST /printers/Checks HTTP/1.1" 200 142 Get-Job-Attributes successful-ok

Again, with debug set this is what I see when my app calls lpr:
localhost - - [04/Oct/2007:08:33:27 -0400] "POST / HTTP/1.1" 200 418 CUPS-Get-Printers successful-ok
localhost - - [04/Oct/2007:08:33:27 -0400] "POST / HTTP/1.1" 200 418 CUPS-Get-Classes successful-ok
localhost - - [04/Oct/2007:08:33:27 -0400] "POST / HTTP/1.1" 200 75 CUPS-Get-Default successful-ok
localhost - - [04/Oct/2007:08:33:27 -0400] "POST /printers/Checks HTTP/1.1" 200 90582 Print-Job client-error-not-authorized

Any help / ideas would really be appreciated.  Thanks in advance,

Dunc