displayconfig: couldn't connect to X server

Binary package hint: displayconfig-gtk

hardware: amilo 1650G (turion64 ML-32, 1GB, 80GB, radeon express 200m: 1280x800)
software: 7.04 beta up-to-date

everything was working correctly for 3 weeks
after one of apt-get dist-upgrade -- noticed X errors listed below (X Error: BadDevice), but everything was working OK

today:
external monitor connected (first time)
displayconfig set to two monitors (lcd & CRT different content)
after X restart desktop switched to about 2000x1000
displayconfig doest not work anymore

error messages given by displayconfig:

X Error: BadDevice, invalid or uninitialized input device 167
  Major opcode: 144
  Minor opcode: 3
  Resource id: 0x0
Failed to open device
X Error: BadDevice, invalid or uninitialized input device 167
  Major opcode: 144
  Minor opcode: 3
  Resource id: 0x0
Failed to open device
Xlib: connection to ":0.0" refused by server
Xlib: No protocol specified

Traceback (most recent call last):
  File "/usr/bin/displayconfig", line 1720, in <module>
    displayapp = DisplayApp()
  File "/usr/bin/displayconfig", line 437, in __init__
    self.xf86server = xf86misc.XF86Server()
  File "/usr/share/python-support/kde-guidance/xf86misc.py", line 133, in __init __
    raise XF86Error, "Couldn't connect to X server."
xf86misc.XF86Error: Couldn't connect to X server.
Error in sys.excepthook:
Traceback (most recent call last):
  File "/var/lib/python-support/python2.5/apport_python_hook.py", line 44, in ap port_excepthook
    binary = os.path.realpath(os.path.join(os.getcwdu(), sys.argv[0]))
IndexError: list index out of range

Original exception was:
Traceback (most recent call last):
  File "/usr/bin/displayconfig", line 1720, in <module>
    displayapp = DisplayApp()
  File "/usr/bin/displayconfig", line 437, in __init__
    self.xf86server = xf86misc.XF86Server()
  File "/usr/share/python-support/kde-guidance/xf86misc.py", line 133, in __init __
    raise XF86Error, "Couldn't connect to X server."
xf86misc.XF86Error: Couldn't connect to X server.
u@u-laptop:~$ sudo displayconfig
X Error: BadDevice, invalid or uninitialized input device 167
  Major opcode: 144
  Minor opcode: 3
  Resource id: 0x0
Failed to open device
X Error: BadDevice, invalid or uninitialized input device 167
  Major opcode: 144
  Minor opcode: 3
  Resource id: 0x0
Failed to open device
Xlib: connection to ":0.0" refused by server
Xlib: No protocol specified

Traceback (most recent call last):
  File "/usr/bin/displayconfig", line 1720, in <module>
    displayapp = DisplayApp()
  File "/usr/bin/displayconfig", line 437, in __init__
    self.xf86server = xf86misc.XF86Server()
  File "/usr/share/python-support/kde-guidance/xf86misc.py", line 133, in __init__
    raise XF86Error, "Couldn't connect to X server."
xf86misc.XF86Error: Couldn't connect to X server.
Error in sys.excepthook:
Traceback (most recent call last):
  File "/var/lib/python-support/python2.5/apport_python_hook.py", line 44, in apport_excepthook
    binary = os.path.realpath(os.path.join(os.getcwdu(), sys.argv[0]))
IndexError: list index out of range

Original exception was:
Traceback (most recent call last):
  File "/usr/bin/displayconfig", line 1720, in <module>
    displayapp = DisplayApp()
  File "/usr/bin/displayconfig", line 437, in __init__
    self.xf86server = xf86misc.XF86Server()
  File "/usr/share/python-support/kde-guidance/xf86misc.py", line 133, in __init__
    raise XF86Error, "Couldn't connect to X server."
xf86misc.XF86Error: Couldn't connect to X server.