device communication error code 5012

I have a HP PSC 750, it was fully working on Karmic, after a new fresh installation of Lucid Lynx, it has stopped working at all, I'm not able to scan nor print. "hp-toolbox" says "device communication error (5012)"
The printer is plugged directly to the usb port, and I have already tried plug it on different ports, using different cables unplug/re-plug, reboot, even printer full reset (the "hardware reset" holding the buttons and plugging the power cord). And re-installing (via synaptic) all hplip, cups and dependencies.

lsusb is allways showing the printer
---------------------
$ lsusb
(...)
Bus 006 Device 003: ID 03f0:1411 Hewlett-Packard PSC 750
(...)

----------------------

$ hp-check

HP Linux Imaging and Printing System (ver. 3.10.2)
Dependency/Version Check Utility ver. 14.3

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.

Note: hp-check can be run in three modes:
1. Compile-time check mode (-c or --compile): Use this mode before compiling the
HPLIP supplied tarball (.tar.gz or .run) to determine if the proper dependencies
are installed to successfully compile HPLIP.
2. Run-time check mode (-r or --run): Use this mode to determine if a distro
supplied package (.deb, .rpm, etc) or an already built HPLIP supplied tarball
has the proper dependencies installed to successfully run.
3. Both compile- and run-time check mode (-b or --both) (Default): This mode
will check both of the above cases (both compile- and run-time dependencies).

Saving output in log file: hp-check.log

Initializing. Please wait...

---------------
| SYSTEM INFO |
---------------

Basic system information:
Linux jorgemarmo-laptop 2.6.32-23-generic #37-Ubuntu SMP Fri Jun 11 08:03:28 UTC 2010 x86_64 GNU/Linux

Distribution:
ubuntu 10.04

Checking Python version...
OK, version 2.6.5 installed

Checking PyQt 4.x version...
OK, version 4.7.2 installed.

Checking for CUPS...
Status: scheduler is running
Version: 1.4.3
error_log is set to level: warn

Checking for dbus/python-dbus...
dbus daemon is running.
python-dbus version: 0.83.0

------------------------------------
| COMPILE AND RUNTIME DEPENDENCIES |
------------------------------------

note: To check for compile-time only dependencies, re-run hp-check with the -c parameter (ie, hp-check -c).
note: To check for run-time only dependencies, re-run hp-check with the -r parameter (ie, hp-check -r).

Checking for dependency: CUPS - Common Unix Printing System...
OK, found.

Checking for dependency: CUPS devel- Common Unix Printing System development files...
OK, found.

Checking for dependency: CUPS image - CUPS image development files...
OK, found.

Checking for dependency: DBus - Message bus system...
OK, found.

Checking for dependency: gcc - GNU Project C and C++ Compiler...
OK, found.

Checking for dependency: GhostScript - PostScript and PDF language interpreter and previewer...
OK, found.

Checking for dependency: libcrypto - OpenSSL cryptographic library...
OK, found.

Checking for dependency: libjpeg - JPEG library...
OK, found.

Checking for dependency: libnetsnmp-devel - SNMP networking library development files...
OK, found.

Checking for dependency: libpthread - POSIX threads library...
OK, found.

Checking for dependency: libtool - Library building support services...
OK, found.

Checking for dependency: libusb - USB library...
OK, found.

Checking for dependency: make - GNU make utility to maintain groups of programs...
OK, found.

Checking for dependency: PIL - Python Imaging Library (required for commandline scanning with hp-scan)...
OK, found.

Checking for dependency: PolicyKit - Administrative policy framework...
OK, found.

Checking for dependency: PyQt 4 DBus - DBus Support for PyQt4...
OK, found.

Checking for dependency: Python DBus - Python bindings for DBus...
OK, found.

Checking for dependency: Python devel - Python development files...
OK, found.

Checking for dependency: Python libnotify - Python bindings for the libnotify Desktop notifications...
OK, found.

Checking for dependency: Python XML libraries...
OK, found.

Checking for dependency: Python 2.3 or greater - Required for fax functionality...
OK, found.

Checking for dependency: Python 2.2 or greater - Python programming language...
OK, found.

Checking for dependency: Reportlab - PDF library for Python...
OK, found.

Checking for dependency: SANE - Scanning library...
OK, found.

Checking for dependency: SANE - Scanning library development files...
OK, found.

Checking for dependency: scanimage - Shell scanning program...
OK, found.

Checking for dependency: xsane - Graphical scanner frontend for SANE...
OK, found.

----------------------
| HPLIP INSTALLATION |
----------------------

Currently installed HPLIP version...
HPLIP 3.10.2 currently installed in '/usr/share/hplip'.

Current contents of '/etc/hp/hplip.conf' file:
# hplip.conf. Generated from hplip.conf.in by configure.

[hplip]
version=3.10.2

[dirs]
home=/usr/share/hplip
run=/var/run
ppd=/usr/share/ppd/hplip/HP
ppdbase=/usr/share/ppd/hplip
doc=/usr/share/doc/hplip-doc/HTML
icon=no
cupsbackend=/usr/lib/cups/backend
cupsfilter=/usr/lib/cups/filter
drv=/usr/share/cups/drv

# Following values are determined at configure time and cannot be changed.
[configure]
network-build=yes
pp-build=yes
gui-build=yes
scanner-build=yes
fax-build=yes
dbus-build=yes
cups11-build=no
doc-build=yes
shadow-build=no
hpijs-install=yes
foomatic-drv-install=yes
foomatic-ppd-install=yes
foomatic-rip-hplip-install=no
hpcups-install=yes
cups-drv-install=yes
cups-ppd-install=no
internal-tag=3.10.2rc1.9
restricted-build=no
ui-toolkit=qt4
qt3=no
qt4=yes
policy-kit=yes
hpijs-only-build=no
lite-build=no
udev-acl-rules=yes
hpcups-only-build=no
hpijs-only-build=no

Current contents of '/var/lib/hp/hplip.state' file:
# hplip.state - HPLIP runtime persistent variables.

[plugin]
installed=0
eula=0

Current contents of '~/.hplip/hplip.conf' file:
[last_used]
printer_name =
working_dir = .
device_uri = "hp:/usb/PSC_750?serial=MY173B20B9WB"

[commands]
scan = /usr/bin/simple-scan %SANE_URI%

[installation]
version = 3.10.2rc1.9
date_time = 07/15/2010 18:23:55

[settings]
systray_messages = 0
systray_visible = 0

[fax]
email_address =
voice_phone =

[refresh]
rate = 30
enable = false
type = 1

[polling]
enable = false
device_list =
interval = 5

--------------------------
| DISCOVERED USB DEVICES |
--------------------------

  Device URI Model
  -------------------------------- ----------------
  hp:/usb/PSC_750?serial=MY173B20B HP PSC 750
  9WB

---------------------------------
| INSTALLED CUPS PRINTER QUEUES |
---------------------------------

Deskjet-D1400-series
--------------------
Type: Printer
Device URI: hp:/usb/Deskjet_D1400_series?serial=CN7AO3N36904Y1
PPD: /etc/cups/ppd/Deskjet-D1400-series.ppd
PPD Description: HP Deskjet d1400 Series hpijs, 3.10.2rc1.9
Printer status: printer Deskjet-D1400-series disabled since Thu 15 Jul 2010 05:31:53 PM Unplugged or turned off

HP Linux Imaging and Printing System (ver. 3.10.2)
System Tray Status Service ver. 2.0

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.

/usr/lib/pymodules/python2.6/gtk-2.0/gtk/__init__.py:127: RuntimeWarning: PyOS_InputHook is not available for interactive use of PyGTK
  set_interactive(1)
error: Unable to communicate with device (code=12): hp:/usb/Deskjet_D1400_series?serial=CN7AO3N36904Y1
error: Device not found
error: Communication status: Failed

PSC-750
-------
Type: Printer
Device URI: hp:/usb/PSC_750?serial=MY173B20B9WB
PPD: /etc/cups/ppd/PSC-750.ppd
PPD Description: HP PSC 750 hpijs, 3.10.2rc1.9
Printer status: printer PSC-750 is idle. enabled since Thu 15 Jul 2010 06:16:57 PM VET
error: Device busy: hp:/usb/PSC_750?serial=MY173B20B9WB
error: Device not found
error: Communication status: Failed

----------------------
| SANE CONFIGURATION |
----------------------

'hpaio' in '/etc/sane.d/dll.conf'...
OK, found. SANE backend 'hpaio' is properly set up.

Checking output of 'scanimage -L'...
device `hpaio:/usb/PSC_750?serial=MY173B20B9WB' is a Hewlett-Packard PSC_750 all-in-one

---------------------
| PYTHON EXTENSIONS |
---------------------

Checking 'cupsext' CUPS extension...
OK, found.

Checking 'pcardext' Photocard extension...
OK, found.

Checking 'hpmudext' I/O extension...
OK, found.

Checking 'scanext' SANE scanning extension...
OK, found.

-----------------
| USB I/O SETUP |
-----------------

Checking for permissions of USB attached printers...

HP Device 0x1411 at 006:003:
    Device URI: hp:/usb/PSC_750?serial=MY173B20B9WB
    Device node: /dev/bus/usb/006/003
    Mode: 0664

---------------
| USER GROUPS |
---------------

jorgemarmo adm lp dialout cdrom plugdev lpadmin admin sambashare

User member of group 'lp'. Enables print/ scan/ fax.
User member of group 'lpadmin'.

-----------
| SUMMARY |
-----------

error: 2 errors and/or warnings.

Please refer to the installation instructions at:
http://hplip.sourceforge.net/install/index.html

Done.
-----------------------------------------------------------------------------------------------
-----------------------------------------------------------------------------------------------
Note: the second printer shown there (the D1400), is not plugged right now, but it works.

Thanks you in advance for all your replies, comments and suggestions.