CUPS stopped accepting requests

[Olli Vaananen]

I have SuSe 10.1 with CUPS version 1.1.23. CUPS came with SuSe, I didn't install it myself.
I installed HP Photosmart C4480 printer a few days ago. This model is not included in the list of installed drivers, but I used the PPD of Photosmart 3300 instead, and everything went fine. The printer worked a few days exactly the way it should.
But suddenly something happened, and the printer stopped responding. Yast2 (the administrative tool of SuSe) tells, that the connection between the computer and the printer is allright (testing the connection makes the printer to print words "Hello World"), but when Yast2 tries to test the PPD file, a message is given:
"When saving a string y2test there was an error when sending a message to CUPS-server.
cups(File)DoRequest error: client-error-bad-request"

After this unsuccessful test, the system log shows these three lines:
"Dec 18 23:19:08 piika hp: unable to open /var/run/hpiod.port: No such file or directory: prnt/hpijs/hplip_api.c 84
Dec 18 23:19:08 piika hp: unable to connect hpiod socket 50000: Connection refused: prnt/hpijs/hplip_api.c 703
Dec 18 23:19:08 piika hp: unable to send ProbeDevices: Broken pipe"

When trying to  print something from the text editor (unsuccessfully), nothing is  shown in the system log.

Am I correct assuming the "Broken pipe" is situated between the text editor and CUPS, not between CUPS and the printer?

Where is the script that asks for "prnt/hpijs/hplip_api.c 84" to open. I went through cups-config and cupsd.conf but could find nothing referring to this missing file. In printers.conf I found a line "StateMessage Unable to open USB device  'usb://HP/Photosmart%20C440%series?serial=TH859D158KO557':No such device"

Who broke the pipe? Why did it work first and then stopped working?