Without any info from the logs there is nothing I can do.
Of course I can print from applications (in particular from kwrite).
Therefore you must provide sufficient information so that I
have a chance to find out what your problem is.

Yes, that´s no problem. I just don´t know (in case of KDE apps) what I should
send you since I don´t see any logs. Do you know a suitable app for that?

First test whether printing works from command line like
lp -d <queue> /etc/SuSE-release
which should print the Suse release plain text file
or for PostScript file printing use
lp -d <queue> /usr/share/doc/packages/ghostscript/examples/colorcir.ps
which should print the color ellipse.
Replace <queu> with the printer queue name.

If this doesn't work see
http://portal.suse.com/sdb/en/2004/05/jsmeix_print-cups-in-a-nutshell.html
how to get CUPS log messages:
---------------------------------------------------------------
If problems are encountered:
1.
Set the "LogLevel debug" in /etc/cups/cupsd.conf.
2.
Stop cupsd.
3.
Move /var/log/cups/error_log* to another location (or delete it)
in order to avoid having to search through gigantic log files.
4.
Start cupsd.
5.
Retry the action leading to the problem.
6.
Now /var/log/cups/error_log contains many messages
that are useful for troubleshooting. 
---------------------------------------------------------------
Attach /var/log/cups/error_log as plain text file to this bug.

If printing from command line works, it is a KDE problem.
See "How to report a KDE bug" at
http://www.opensuse.org/Submit_a_bug

OK, printing from the commandline works fine as well as from GNOME.Unfortunately
the logfiles mentioned in "how to report a KDE bug" either don´t exist or don´t
contain something useful. 
In SuSE 9.3 printing worked well in KDE. And isn´t the KDE version the same as
in 9.3?
Is there anything I can further help with finding the cause since printing is
very important for me.

A workaround:
Switch in the KDE printing dialog (via [Options])
from "CUPS (Common Unix Print System)"
to "Print through an external program (generic)"
and enter as "Print command" something like
lp -d <queue>
or for example
xpp
(/usr/bin/xpp is another graphical printing frontend in the package xpp)
or
gtklp
or whatever external print command you prefer.

Yes this workaround works.
Is this a known bug or what can I do to help fixing it?

It´s still the same with 10.1 Alpha1.

Sorry if this is annoying, but I experience this now with 2 computers so I think this is not a very rare problem.
Printing is essential IMHO so could something be done about this?

I just saw that the KDE print management doesn´t show the printers I configured with YaST any more. Perhaps this should be solved first.

But they are shown from http://localhost:631/printers ? Does kdeprint show you to what it's connected to? As it works for so many others, something must be setup wrong. Perhaps a strace of kdeprint can reveal the problem.

sorry, replace kdeprint with kprinter above

OK is was wrong. I tried to use the workaround by Johannes Meisner and changed to "print through external program". But I didn´t find the "Print command" entry field. Where can I find it?
And still I´d help in finding the "real" problem.

still, kprinter is the tool you want to debug first.

OK, how sahould I start?

kprinter /etc/groups - see what error you get.

There´s no error, it was my fault.
I entered "lp -d stylusc86" as the print command and the workaround works now.

I just tested and there is also no printing from firefox using CUPS. It´s the same as with KDE just nothing is printed, I don´t get any error.

if it's the same with firefox, I guess it's time we give you to the experts that can ask expert questions

As "printing from the commandline works fine as well as from GNOME"
(se comment #4), it is no problem in CUPS.

I have neither an idea why it doesn't work from KDE (I am no KDE expert)
nor do I have an idea why firefox cannot print (I am no firefox expert)
nor do I know how to debug KDE and/or firefox.
I suggest the KDE experts debug the KDE part and a new bug report
is made regarding the firefox problem.

Michael,
please open a new bug report regarding your firefox printing problem.

well, firefox does not use the "KDE part"

back to #15

/etc/groups doesn´t exist on my system, so I tried to print /etc/group (I disabled the workaround and switched back to using CUPS).
I was asked about converting the data before printing, I poressed "convert" and kprinter displayed the progress dialog and then closed.
I could see this in the console:

michael@r098088:~> kprinter /etc/group
[ 1 pages * 1 copy ] left in /tmp/kde-michael/kdeprint_2HQHb4rz

When I didn´t convert the data this line didn´t appear, so kprinter didn´t return an error message or something. But there is no printing done :(

To log what CUPS does in this case, see
http://portal.suse.com/sdb/en/2004/05/jsmeix_print-cups-in-a-nutshell.html
"If problems are encountered":

1.
Set the "LogLevel debug" in /etc/cups/cupsd.conf.
2.
Stop cupsd.
3.
Move /var/log/cups/error_log* to another location (or delete it)
in order to avoid having to search through gigantic log files
4.
Start cupsd.
5.
Retry the action leading to the problem.
6.
Now /var/log/cups/error_log* contains many messages
that are useful for troubleshooting. 

Directly after one single failed test print, copy the log like
cp /var/log/cups/error_log /tmp/cups.error_log
and then attach /tmp/cups.error_log to the bug as plain text attachment.

Created attachment 55342 [details]
CUPS error log with loglevel "debug"

I tried to print /etc/group and attached the CUPS log

The logfile doesn't contain the relevant part. It's flooded with other stuff,
which looks like, that you enabled "debug2" instead of "debug"  in /etc/cups/cupsd.conf. :(

Please try again.

Do the following steps (1-4) as user "root", the rest can be done as any user.

1. stop your cups daemon
   rccups stop
2. edit /etc/cups/cupsd.conf
   LogLevel debug
3. remove old logfiles
   rm /var/log/cups/error_log
4. start cups daemon again
   rccups start
5. print file /etc/group
   kprinter /etc/group
6. Attache error_log to this bugzilla entry

Thanks in advance.

Created attachment 55360 [details]
new CUPS error log

I attached a new log. The loglevel was and is set to "debug", not "debug2"

Thanks.

Sorry, but it looked very like "debug2" output.

Nevertheless, the logfile misses the relevant again. :-( 
You don't have a file named /var/log/cups/error_log.O at your host which you can attache here?

Created attachment 55372 [details]
errorlog.o

I attached the error_log.O.

Again the error_log is full of useless debug messages
I guess from the driver - unfortunately some drivers produce
much too much debug messages :-(
Which driver do you use?
(Simply attach the PPD file from /etc/cups/ppd/<queue>.ppd
 as plain text to this bug.)

Please try again with "LogLevel info" and please use
explicitely the mime type "text/plain" for the attachments
(otherwise it falls back to "application/octet-stream" which cannot
 be viewed directly in a browser - at least not in my Mozilla).

I was using the epson printer driver from www.avasys.co.jp (because there was no support for a C86 in SuSE).
I changed it to use a C84 (which is the US version) and it works from KDE too.
Strange that the native drivers work from your test program but not from KDE. So I think you can close this bug report. Or if you want to help me debugging this (because SuSE should support the native drivers) then I can test further.

I know that the printer driver(s) from www.avasys.co.jp
are <beeep> <beeep> <beeep> ...  because the printer drivers
are not working in compliance to CUPS.

In contrast the Iscan scanner driver from Epson Avasys 
(at least the actual driver i.e. the "epkowa" backend)
is working in full compliance to SANE.

For example see:
http://lists.alioth.debian.org/pipermail/sane-devel/2005-October/014988.html
-----------------------------------------------------------------------------
A few days ago I tested a proprietary printer driver from
a manufacturer for a low-level all-in-one device.
I set up a CUPS queue to print into a file but this nice
proprietary driver did't care how the queue was set up.
It simply spits out its printer specific binary stuff directly
on the first USB printer (a real good PostScript printer)
which printed tons of sheets with nonsense characters ;-)
-----------------------------------------------------------------------------

It is a valid bug for the Avasys driver
but it is INVLID for Suse Linux.

No, we cannot support such broken-by-design drivers, see
http://portal.suse.com/sdb/en/2003/11/jsmeix_print-info-for-manufacturers.html

We do not have the manpower to re-design such drivers
and we cannot do it in this particular case because crucial parts
of this driver software are not available as open source
(only as proprietary binary-only i386-only library).

Please send a bug report to the authors of this broken driver.

Regarding Firefox:
If it still doesn't print, please open a new bug report
and attach a CUPS error_log for one failed attempt.