HP LaserJet cp1025nw does not print via Network

I'm using HPLIP 3.12.2 on (k)ubuntu 11.10
I've configured HP LaserJet cp1025nw as a USB-printer. Everything seems to work fine.
The log of `hp-check -t` for USB configuration is named hp-check.usb.log in attachments.

Then I've configured the device as network printer (connected it via Ethernet cable to my "ZyXEL KEENETIC" router). The setup program can 'see' the printer on the Network (something like hp:/net/HP_LaserJet_CP1025nw?serial=...), but nevertheless it can't print a test page.
Here's a console log of hp-setup

$ hp-setup

HP Linux Imaging and Printing System (ver. 3.12.2)
Printer/Fax Setup Utility ver. 9.0

Copyright (c) 2001-9 Hewlett-Packard Development Company, LP
This software comes with ABSOLUTELY NO WARRANTY.
This is free software, and you are welcome to distribute it
under certain conditions. See COPYING file for more details.

Searching... (bus=net, timeout=5, ttl=4, search=(None) desc=0, method=mdns)
|error: Unable to communicate with device (code=12): hp:/net/HP_LaserJet_CP1025nw?zc=NPIA732D3
error: Unable to print to printer. Please check device and try again.

Done.

The log `hp-check -t` for Network configuration is named hp-check.net.log in attachments.