Application that crashed: korganizer
Version of the application: 4.3.2
KDE Version: 4.3.2 (KDE 4.3.2)
Qt Version: 4.5.2
Operating System: Linux 2.6.31-20-generic i686
Distribution: Ubuntu 9.10

What I was doing when the application crashed:
the same as a few minutes ago, but this time Korganiser was in the state after a fresh start

 -- Backtrace:
Application: KOrganizer (korganizer), signal: Segmentation fault
[KCrash Handler]
#6  QBasicAtomicInt::ref (this=0x9dbe880) at /usr/include/qt4/QtCore/qatomic_i386.h:120
#7  QString (this=0x9dbe880) at /usr/include/qt4/QtCore/qstring.h:712
#8  KCal::IncidenceBase::uid (this=0x9dbe880) at ../../kcal/incidencebase.cpp:185
#9  0x01dec419 in KOEventViewer::changeIncidenceDisplay (this=0x8c62c28, incidence=0x9c34eb8, action=0) at ../../korganizer/koeventviewer.cpp:136
#10 0x0059546e in CalendarView::changeIncidenceDisplay (this=0x8ad1548, incidence=0x9c34eb8, action=0) at ../../korganizer/calendarview.cpp:786
#11 0x0059fd23 in CalendarView::incidenceAdded (this=0x8ad1548, incidence=0x9c34eb8) at ../../korganizer/calendarview.cpp:659
#12 0x005a6891 in CalendarView::qt_metacall (this=0x8ad1548, _c=QMetaObject::InvokeMetaMethod, _id=92, _a=0xbfd40278) at ./calendarview.moc:484
#13 0x075ed263 in QMetaObject::activate (sender=0x8d5e958, from_signal_index=4, to_signal_index=4, argv=0xbfd40278) at kernel/qobject.cpp:3113
#14 0x075edec2 in QMetaObject::activate (sender=0x8d5e958, m=0x8e5e1c, local_signal_index=0, argv=0xbfd40278) at kernel/qobject.cpp:3187
#15 0x008e4223 in KOrg::IncidenceChangerBase::incidenceAdded (this=0x8d5e958, _t1=0x9c34eb8) at ./incidencechangerbase.moc:94
#16 0x0063ef34 in IncidenceChanger::addIncidence (this=0x8d5e958, incidence=0x9c34eb8, parent=0x8ad1548) at ../../korganizer/incidencechanger.cpp:334
#17 0x0059a0ab in CalendarView::edit_paste (this=0x8ad1548) at ../../korganizer/calendarview.cpp:919
#18 0x005a69e0 in CalendarView::qt_metacall (this=0x8ad1548, _c=QMetaObject::InvokeMetaMethod, _id=105, _a=0xbfd405e8) at ./calendarview.moc:497
#19 0x075ed263 in QMetaObject::activate (sender=0x8dd6fe0, from_signal_index=5, to_signal_index=6, argv=0xbfd405e8) at kernel/qobject.cpp:3113
#20 0x075ed6d8 in QMetaObject::activate (sender=0x8dd6fe0, m=0x1865e48, from_local_signal_index=1, to_local_signal_index=2, argv=0xbfd405e8) at kernel/qobject.cpp:3207
#21 0x00ffd9b1 in QAction::triggered (this=0x8dd6fe0, _t1=false) at .moc/release-shared/moc_qaction.cpp:236
#22 0x00ffef32 in QAction::activate (this=0x8dd6fe0, event=QAction::Trigger) at kernel/qaction.cpp:1160
#23 0x0144c9cc in QMenuPrivate::activateCausedStack (this=0x8e318b8, causedStack=..., action=0x8dd6fe0, action_e=QAction::Trigger, self=true) at widgets/qmenu.cpp:967
#24 0x0145303b in QMenuPrivate::activateAction (this=0x8e318b8, action=0x8dd6fe0, action_e=QAction::Trigger, self=<value optimized out>) at widgets/qmenu.cpp:1060
#25 0x01453bf7 in QMenu::mouseReleaseEvent (this=0x8e310a0, e=0xbfd40d40) at widgets/qmenu.cpp:2254
#26 0x00be51c5 in KMenu::mouseReleaseEvent (this=0x8e310a0, e=0xbfd40d40) at ../../kdeui/widgets/kmenu.cpp:456
#27 0x01059012 in QWidget::event (this=0x8e310a0, event=0xbfd40d40) at kernel/qwidget.cpp:7549
#28 0x01455e34 in QMenu::event (this=0x8e310a0, e=0xbfd40d40) at widgets/qmenu.cpp:2353
#29 0x01003f54 in QApplicationPrivate::notify_helper (this=0x89e52b0, receiver=0x8e310a0, e=0xbfd40d40) at kernel/qapplication.cpp:4056
#30 0x0100c033 in QApplication::notify (this=0xbfd426f4, receiver=0x8e310a0, e=0xbfd40d40) at kernel/qapplication.cpp:3758
#31 0x00afabfa in KApplication::notify (this=0xbfd426f4, receiver=0x8e310a0, event=0xbfd40d40) at ../../kdeui/kernel/kapplication.cpp:302
#32 0x075d76cb in QCoreApplication::notifyInternal (this=0xbfd426f4, receiver=0x8e310a0, event=0xbfd40d40) at kernel/qcoreapplication.cpp:610
#33 0x0100af6e in QCoreApplication::sendSpontaneousEvent (receiver=0x8e310a0, event=0xbfd40d40, alienWidget=0x0, nativeWidget=0x8e310a0, buttonDown=0x187eaa0, lastMouseReceiver=...)
    at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:216
#34 QApplicationPrivate::sendMouseEvent (receiver=0x8e310a0, event=0xbfd40d40, alienWidget=0x0, nativeWidget=0x8e310a0, buttonDown=0x187eaa0, lastMouseReceiver=...) at kernel/qapplication.cpp:2924
#35 0x01079c87 in QETWidget::translateMouseEvent (this=0x8e310a0, event=0xbfd4238c) at kernel/qapplication_x11.cpp:4343
#36 0x01078c4b in QApplication::x11ProcessEvent (this=0xbfd426f4, event=0xbfd4238c) at kernel/qapplication_x11.cpp:3428
#37 0x010a5502 in x11EventSourceDispatch (s=0x89e3d90, callback=0, user_data=0x0) at kernel/qguieventdispatcher_glib.cpp:146
#38 0x0191ee88 in g_main_context_dispatch () from /lib/libglib-2.0.so.0
#39 0x01922730 in ?? () from /lib/libglib-2.0.so.0
#40 0x01922863 in g_main_context_iteration () from /lib/libglib-2.0.so.0
#41 0x0760202c in QEventDispatcherGlib::processEvents (this=0x89b89f8, flags=...) at kernel/qeventdispatcher_glib.cpp:327
#42 0x010a4be5 in QGuiEventDispatcherGlib::processEvents (this=0x89b89f8, flags=...) at kernel/qguieventdispatcher_glib.cpp:202
#43 0x075d5c79 in QEventLoop::processEvents (this=0xbfd42684, flags=) at kernel/qeventloop.cpp:149
#44 0x075d60ca in QEventLoop::exec (this=0xbfd42684, flags=...) at kernel/qeventloop.cpp:201
#45 0x075d853f in QCoreApplication::exec () at kernel/qcoreapplication.cpp:888
#46 0x01003dd7 in QApplication::exec () at kernel/qapplication.cpp:3525
#47 0x0804ec04 in main (argc=1, argv=0xbfd42854) at ../../korganizer/main.cpp:61

Reported using DrKonqi