CUPS gives 'Unable to open the initial device, quitting' when printing to network printer

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http://unix.stackexchange.com – I am trying to print (over Wi-Fi) to an HP Photosmart D110 printer (which is successfully recognized by CUPS). But I only get a sheet with the error message Unable to open the initial device, quitting. And in the CUPS interface it says Filter failed. At home I have an HP Photosmart C3100 that works correctly over USB, so I think CUPS is not the problem. I have tried to no avail: reinstalling cups/hplip pacman -S avahi nss-mdns (like proposed here) The full text of /var/log/cups/error_log is here. I'm running Arch Linux x86-64. What am I missing? (HowTos)