No system tray detected

After some system updates on my openSue 11.1 hp-systray is not working anymore.
I got the error

"error: No system tray detected on this system. Unable to start, exiting."

sudo hp-plugin says
warning: No display found.
error: hp-plugin requires GUI support (try running with --qt3). Try using interactive (-i) mode.

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

Basic system information:
Linux frank 2.6.27.23-0.1-default #1 SMP 2009-05-26 17:02:05 -0400 x86_64 x86_64 x86_64 GNU/Linux

Distribution:
suse 11.1

HPOJ running?
No, HPOJ is not running (OK).

Checking Python version...
OK, version 2.6.0 installed

Checking PyQt 4.x version...
OK, version 4.5 installed.

Checking for CUPS...
Status: Scheduler wird ausgeführt
Version: 1.3.9
warning: /etc/cups/cupsd.conf file not found or not accessible.

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 DDK - CUPS driver development kit...
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...
warning: NOT FOUND! This is an OPTIONAL/RUNTIME ONLY dependency. Some HPLIP functionality may not function properly.

Checking for dependency: ppdev - Parallel port support kernel module....
OK, found.

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

Checking for dependency: Python ctypes - A foreign function library for Python...
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 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 3.9.4b 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=3.9.4b

[dirs]
home=/usr/share/hplip
run=/var/run
ppd=/usr/share/cups/model/manufacturer-PPDs/hplip
ppdbase=/usr/share/cups/model/manufacturer-PPDs
doc=/usr/share/doc/packages/hplip
icon=/usr/share/applications
cupsbackend=/usr/lib64/cups/backend
cupsfilter=/usr/lib64/cups/filter
drv=/usr/share/cups/drv/hp

# 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
foomatic-drv-install=no
foomatic-ppd-install=yes
foomatic-rip-hplip-install=yes
cups-ppd-install=no
cups-drv-install=no
internal-tag=3.9.4b.10
restricted-build=no
ui-toolkit=qt4
qt3=no
qt4=yes
policy-kit=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 = "hpfax:/usb/officejet_5500_series?serial=MY516G126696"

[commands]
scan_int = False
fax = hp-sendfax -d %FAX_URI%
scan = kooka
prnt = hp-print -p%PRINTER%
pcard_int = True
prnt_int = True
pcard = hp-unload -d %DEVICE_URI%
cpy = hp-makecopies -d %DEVICE_URI%
fax_int = True
cpy_int = True

[installation]
version = 3.9.4b.10
date_time = 06/15/09 20:10:17

[settings]
systray_messages = 0
systray_visible = 0

[alerts]
email_from_address =
email_alerts = False
email_to_addresses =

[fax]
email_address =
voice_phone =

[refresh]
rate = 30
enable = false
type = 0

[polling]
enable = false
device_list =
interval = 5

-------------------------------
| DISCOVERED PARALLEL DEVICES |
-------------------------------

No devices found.

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

  Device URI Model
  ------------------------------------------------- --------------------------------
  hp:/usb/officejet_5500_series?serial=MY516G126696 HP officejet 5500 series

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

warning: No queues found.

----------------------
| 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/officejet_5500_series?serial=MY516G126696' is a Hewlett-Packard officejet_5500_series 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 0x3a11 at 002:003:
    Device URI: hp:/usb/officejet_5500_series?serial=MY516G126696
    Device node: /dev/bus/usb/002/003
    Mode: 0664
getfacl: Removing leading '/' from absolute path names
# file: dev/bus/usb/002/003
# owner: lp
# group: lp
user::rw-
user:furban:rw-
group::rw-
mask::rw-
other::r--

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

users disk uucp dialout audio cdrom video

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

error: 1 error or warning.

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

Done.