Version:            (using KDE 4.1.0)
Installed from:    Ubuntu Packages

Updated from Kubuntu 8.04 to 8.10, and same time Kde 3.xx to 4.1 (I think).
This same crash happened in first login, and I was able fix it with:
sudo rm ~/.kde4/share/config/plasmarc
sudo rm ~/.kde4/share/config/plasma-appletrc

sudo rm ~/.kde/share/config/plasmarc
sudo rm ~/.kde/share/config/plasma-appletrc

But Plasma keeps still crashing with dump:
Ohjelma: Plasma-työtila (plasma), signaali SIGSEGV
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[Thread debugging using libthread_db enabled]
[New Thread 0xb47396e0 (LWP 12049)]
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[KCrash handler]
#6  0xb7173527 in QGraphicsLinearLayout::insertItem ()
   from /usr/lib/libQtGui.so.4
#7  0xb2aac887 in ?? () from /usr/lib/kde4/plasma_applet_devicenotifier.so
#8  0xb2aaca27 in ?? () from /usr/lib/kde4/plasma_applet_devicenotifier.so
#9  0xb7d1d585 in Plasma::Applet::flushPendingConstraintsEvents ()
   from /usr/lib/libplasma.so.2
#10 0xb7d1dbc6 in Plasma::Applet::timerEvent () from /usr/lib/libplasma.so.2
#11 0xb763d53f in QObject::event () from /usr/lib/libQtCore.so.4
#12 0xb7176447 in QGraphicsWidget::event () from /usr/lib/libQtGui.so.4
#13 0xb6bb68ec in QApplicationPrivate::notify_helper ()
   from /usr/lib/libQtGui.so.4
#14 0xb6bbe72e in QApplication::notify () from /usr/lib/libQtGui.so.4
#15 0xb7afcb2d in KApplication::notify () from /usr/lib/libkdeui.so.5
#16 0xb762de61 in QCoreApplication::notifyInternal ()
   from /usr/lib/libQtCore.so.4
#17 0xb765bd81 in ?? () from /usr/lib/libQtCore.so.4
#18 0xb7658520 in ?? () from /usr/lib/libQtCore.so.4
#19 0xb59396f8 in g_main_context_dispatch () from /usr/lib/libglib-2.0.so.0
#20 0xb593cda3 in ?? () from /usr/lib/libglib-2.0.so.0
#21 0xb593cf61 in g_main_context_iteration () from /usr/lib/libglib-2.0.so.0
#22 0xb7658478 in QEventDispatcherGlib::processEvents ()
   from /usr/lib/libQtCore.so.4
#23 0xb6c50ea5 in ?? () from /usr/lib/libQtGui.so.4
#24 0xb762c52a in QEventLoop::processEvents () from /usr/lib/libQtCore.so.4
#25 0xb762c6ea in QEventLoop::exec () from /usr/lib/libQtCore.so.4
#26 0xb686b3eb in KIO::NetAccess::enter_loop () from /usr/lib/libkio.so.5
#27 0xb686b5ec in KIO::NetAccess::statInternal () from /usr/lib/libkio.so.5
#28 0xb686c3fb in KIO::NetAccess::stat () from /usr/lib/libkio.so.5
#29 0xb686c47b in KIO::NetAccess::mostLocalUrl () from /usr/lib/libkio.so.5
#30 0xb2b39f1e in ?? () from /usr/lib/kde4/plasma_applet_icon.so
#31 0xb2b3a6ff in ?? () from /usr/lib/kde4/plasma_applet_icon.so
#32 0xb7d4d737 in Plasma::Corona::loadLayout () from /usr/lib/libplasma.so.2
#33 0xb7d4e531 in Plasma::Corona::initializeLayout ()
   from /usr/lib/libplasma.so.2
#34 0xb7fb3199 in ?? () from /usr/lib/libkdeinit4_plasma.so
#35 0xb7fb4880 in ?? () from /usr/lib/libkdeinit4_plasma.so
#36 0xb7fb6a81 in ?? () from /usr/lib/libkdeinit4_plasma.so
#37 0xb7fa843a in kdemain () from /usr/lib/libkdeinit4_plasma.so
#38 0x080485b2 in _start ()
#0  0xb7ffa430 in __kernel_vsyscall ()

And dmesg:
[ 7503.848432] compiz.real[11495]: segfault at 4 ip b7dbbf7b sp bf9f89e0 error 4 in libGL.so.177.82[b7d51000+87000]
[ 7811.722050] plasma[12055]: segfault at 610063 ip b7217527 sp bf99ec50 error 4 in libQtGui.so.4.4.3[b6b20000+8dd000]