Application that crashed: kontact
Version of the application: 4.3.2
KDE Version: 4.3.2 (KDE 4.3.2)
Qt Version: 4.5.2
Operating System: Linux 2.6.31-15-generic x86_64
Distribution: Ubuntu 9.10

What I was doing when the application crashed:
I open Kontakt and look at the Calendar for example. When I'm done, I click on the close x and have two icons in the tray: the Korganizer daemon's and the RSS Akregator's, then there comes the error message and the latter icon disappears. Reproduceable.

 -- Backtrace:
Application: Kontact (kontact), signal: Segmentation fault
[KCrash Handler]
#5  QCoreApplication::notifyInternal (this=0x7fffe449e5d0, receiver=0x0, event=0x7fffe449cc40) at kernel/qcoreapplication.cpp:594
#6  0x00007f8df2839c2a in QCoreApplication::sendEvent (this=<value optimized out>, event=0x7fffe449cc40) at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:213
#7  QWidget::event (this=<value optimized out>, event=0x7fffe449cc40) at kernel/qwidget.cpp:7845
#8  0x00007f8df27eaefc in QApplicationPrivate::notify_helper (this=0x8f9da0, receiver=0xdb9c00, e=0x7fffe449cc40) at kernel/qapplication.cpp:4056
#9  0x00007f8df27f21ce in QApplication::notify (this=0x7fffe449e5d0, receiver=0xdb9c00, e=0x7fffe449cc40) at kernel/qapplication.cpp:4021
#10 0x00007f8df3421ab6 in KApplication::notify (this=0x7fffe449e5d0, receiver=0xdb9c00, event=0x7fffe449cc40) at ../../kdeui/kernel/kapplication.cpp:302
#11 0x00007f8df1ecac2c in QCoreApplication::notifyInternal (this=0x7fffe449e5d0, receiver=0xdb9c00, event=0x7fffe449cc40) at kernel/qcoreapplication.cpp:610
#12 0x00007f8df2839c2a in QCoreApplication::sendEvent (this=<value optimized out>, event=0x7fffe449cc40) at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:213
#13 QWidget::event (this=<value optimized out>, event=0x7fffe449cc40) at kernel/qwidget.cpp:7845
#14 0x00007f8df2b952a6 in QFrame::event (this=0xaa33a0, e=0x7fffe449cc40) at widgets/qframe.cpp:559
#15 0x00007f8df27eaefc in QApplicationPrivate::notify_helper (this=0x8f9da0, receiver=0xaa33a0, e=0x7fffe449cc40) at kernel/qapplication.cpp:4056
#16 0x00007f8df27f21ce in QApplication::notify (this=0x7fffe449e5d0, receiver=0xaa33a0, e=0x7fffe449cc40) at kernel/qapplication.cpp:4021
#17 0x00007f8df3421ab6 in KApplication::notify (this=0x7fffe449e5d0, receiver=0xaa33a0, event=0x7fffe449cc40) at ../../kdeui/kernel/kapplication.cpp:302
#18 0x00007f8df1ecac2c in QCoreApplication::notifyInternal (this=0x7fffe449e5d0, receiver=0xaa33a0, event=0x7fffe449cc40) at kernel/qcoreapplication.cpp:610
#19 0x00007f8df2839c2a in QCoreApplication::sendEvent (this=<value optimized out>, event=0x7fffe449cc40) at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:213
#20 QWidget::event (this=<value optimized out>, event=0x7fffe449cc40) at kernel/qwidget.cpp:7845
#21 0x00007f8df27eaefc in QApplicationPrivate::notify_helper (this=0x8f9da0, receiver=0xa9c860, e=0x7fffe449cc40) at kernel/qapplication.cpp:4056
#22 0x00007f8df27f21ce in QApplication::notify (this=0x7fffe449e5d0, receiver=0xa9c860, e=0x7fffe449cc40) at kernel/qapplication.cpp:4021
#23 0x00007f8df3421ab6 in KApplication::notify (this=0x7fffe449e5d0, receiver=0xa9c860, event=0x7fffe449cc40) at ../../kdeui/kernel/kapplication.cpp:302
#24 0x00007f8df1ecac2c in QCoreApplication::notifyInternal (this=0x7fffe449e5d0, receiver=0xa9c860, event=0x7fffe449cc40) at kernel/qcoreapplication.cpp:610
#25 0x00007f8df2839c2a in QCoreApplication::sendEvent (this=<value optimized out>, event=0x7fffe449cc40) at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:213
#26 QWidget::event (this=<value optimized out>, event=0x7fffe449cc40) at kernel/qwidget.cpp:7845
#27 0x00007f8df27eaefc in QApplicationPrivate::notify_helper (this=0x8f9da0, receiver=0x93bd00, e=0x7fffe449cc40) at kernel/qapplication.cpp:4056
#28 0x00007f8df27f21ce in QApplication::notify (this=0x7fffe449e5d0, receiver=0x93bd00, e=0x7fffe449cc40) at kernel/qapplication.cpp:4021
#29 0x00007f8df3421ab6 in KApplication::notify (this=0x7fffe449e5d0, receiver=0x93bd00, event=0x7fffe449cc40) at ../../kdeui/kernel/kapplication.cpp:302
#30 0x00007f8df1ecac2c in QCoreApplication::notifyInternal (this=0x7fffe449e5d0, receiver=0x93bd00, event=0x7fffe449cc40) at kernel/qcoreapplication.cpp:610
#31 0x00007f8df2839c2a in QCoreApplication::sendEvent (this=<value optimized out>, event=0x7fffe449cc40) at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:213
#32 QWidget::event (this=<value optimized out>, event=0x7fffe449cc40) at kernel/qwidget.cpp:7845
#33 0x00007f8df2baf9db in QMainWindow::event (this=0x8f4200, event=0x7fffe449cc40) at widgets/qmainwindow.cpp:1399
#34 0x00007f8df352d773 in KXmlGuiWindow::event (this=0x3, ev=0x0) at ../../kdeui/xmlgui/kxmlguiwindow.cpp:131
#35 0x00007f8df27eaefc in QApplicationPrivate::notify_helper (this=0x8f9da0, receiver=0x8f4200, e=0x7fffe449cc40) at kernel/qapplication.cpp:4056
#36 0x00007f8df27f21ce in QApplication::notify (this=0x7fffe449e5d0, receiver=0x8f4200, e=0x7fffe449cc40) at kernel/qapplication.cpp:4021
#37 0x00007f8df3421ab6 in KApplication::notify (this=0x7fffe449e5d0, receiver=0x8f4200, event=0x7fffe449cc40) at ../../kdeui/kernel/kapplication.cpp:302
#38 0x00007f8df1ecac2c in QCoreApplication::notifyInternal (this=0x7fffe449e5d0, receiver=0x8f4200, event=0x7fffe449cc40) at kernel/qcoreapplication.cpp:610
#39 0x00007f8df27f0b59 in QCoreApplication::sendEvent (widget=<value optimized out>) at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:213
#40 QApplicationPrivate::enterModal (widget=<value optimized out>) at kernel/qapplication.cpp:2777
#41 0x00007f8df283eb85 in QWidgetPrivate::show_helper (this=0x16ac800) at kernel/qwidget.cpp:6761
#42 0x00007f8df283fbba in QWidget::setVisible (this=0x19c2830, visible=<value optimized out>) at kernel/qwidget.cpp:6975
#43 0x00007f8df2c6667c in QDialog::setVisible (this=0x19c2830, visible=<value optimized out>) at dialogs/qdialog.cpp:706
#44 0x00007f8df2c65995 in QWidget::show (this=0x19c2830) at ../../include/QtGui/../../src/gui/kernel/qwidget.h:473
#45 QDialog::exec (this=0x19c2830) at dialogs/qdialog.cpp:489
#46 0x00007f8df33a8185 in KMessageBox::createKMessageBox (dialog=<value optimized out>, icon=<value optimized out>, text=<value optimized out>, strlist=<value optimized out>, 
    ask=<value optimized out>, checkboxReturn=<value optimized out>, options=) at ../../kdeui/dialogs/kmessagebox.cpp:331
#47 0x00007f8df33a9400 in KMessageBox::createKMessageBox (dialog=<value optimized out>, icon=QMessageBox::Critical, text=<value optimized out>, strlist=<value optimized out>, ask=..., 
    checkboxReturn=0x0, options=..., details=...) at ../../kdeui/dialogs/kmessagebox.cpp:151
#48 0x00007f8df33aa2c3 in KMessageBox::errorListWId (parent_id=58720281, text=..., strlist=..., caption=..., options=) at ../../kdeui/dialogs/kmessagebox.cpp:849
#49 0x00007f8df33aa4c2 in KMessageBox::error (parent=<value optimized out>, text=..., caption=..., options=<value optimized out>) at ../../kdeui/dialogs/kmessagebox.cpp:813
#50 0x00007f8def21bffe in KABC::GuiErrorHandler::error(QString const&) () from /usr/lib/libkabc.so.4
#51 0x00007f8def2016a9 in KABC::AddressBook::error(QString const&) () from /usr/lib/libkabc.so.4
#52 0x00007f8dd346b745 in KABC::ResourceFile::requestSaveTicket() () from /usr/lib/libkabc_file_core.so.4
#53 0x00007f8def1ffb9e in KABC::AddressBook::requestSaveTicket(KABC::Resource*) () from /usr/lib/libkabc.so.4
#54 0x00007f8def22b202 in KABC::StdAddressBook::Private::saveAll() () from /usr/lib/libkabc.so.4
#55 0x00007f8def22b427 in KABC::StdAddressBook::~StdAddressBook() () from /usr/lib/libkabc.so.4
#56 0x00007f8def22a656 in KABC::StdAddressBook::close() () from /usr/lib/libkabc.so.4
#57 0x00007f8dd18eb6d0 in KABCore::~KABCore() () from /usr/lib/libkaddressbookprivate.so.4
#58 0x00007f8df1ed8e5c in QObjectPrivate::deleteChildren (this=0xdb65a0) at kernel/qobject.cpp:1847
#59 0x00007f8df28354f3 in ~QWidget (this=0xdb9c00, __in_chrg=<value optimized out>) at kernel/qwidget.cpp:1367
#60 0x00007f8df14e1594 in ~Part (this=0x18f2760, __vtt_parm=0x7f8dd1d68630, __in_chrg=<value optimized out>) at ../../kparts/part.cpp:208
#61 0x00007f8dd1b652eb in ?? () from /usr/lib/kde4/kaddressbookpart.so
#62 0x00007f8df3b6fdae in Kontact::Plugin::~Plugin() () from /usr/lib/libkontactinterfaces.so.4
#63 0x00007f8ddd0c5ca5 in ?? () from /usr/lib/kde4/kontact_kaddressbookplugin.so
#64 0x00007f8df3d91e0f in Kontact::MainWindow::~MainWindow() () from /usr/lib/libkontactprivate.so.4
#65 0x00007f8df1eda11d in QObject::event (this=0x8f4200, e=0x0) at kernel/qobject.cpp:1094
#66 0x00007f8df283915f in QWidget::event (this=0x8f4200, event=0x226b820) at kernel/qwidget.cpp:7946
#67 0x00007f8df2baf9db in QMainWindow::event (this=0x8f4200, event=0x226b820) at widgets/qmainwindow.cpp:1399
#68 0x00007f8df352d773 in KXmlGuiWindow::event (this=0x3, ev=0x0) at ../../kdeui/xmlgui/kxmlguiwindow.cpp:131
#69 0x00007f8df27eaefc in QApplicationPrivate::notify_helper (this=0x8f9da0, receiver=0x8f4200, e=0x226b820) at kernel/qapplication.cpp:4056
#70 0x00007f8df27f21ce in QApplication::notify (this=0x7fffe449e5d0, receiver=0x8f4200, e=0x226b820) at kernel/qapplication.cpp:4021
#71 0x00007f8df3421ab6 in KApplication::notify (this=0x7fffe449e5d0, receiver=0x8f4200, event=0x226b820) at ../../kdeui/kernel/kapplication.cpp:302
#72 0x00007f8df1ecac2c in QCoreApplication::notifyInternal (this=0x7fffe449e5d0, receiver=0x8f4200, event=0x226b820) at kernel/qcoreapplication.cpp:610
#73 0x00007f8df1ecb80a in QCoreApplication::sendEvent (receiver=0x0, event_type=<value optimized out>, data=0x8be080) at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:213
#74 QCoreApplicationPrivate::sendPostedEvents (receiver=0x0, event_type=<value optimized out>, data=0x8be080) at kernel/qcoreapplication.cpp:1247
#75 0x00007f8df1ef3533 in QCoreApplication::sendPostedEvents (s=<value optimized out>) at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:218
#76 postEventSourceDispatch (s=<value optimized out>) at kernel/qeventdispatcher_glib.cpp:210
#77 0x00007f8deb744bbe in g_main_context_dispatch () from /lib/libglib-2.0.so.0
#78 0x00007f8deb748588 in ?? () from /lib/libglib-2.0.so.0
#79 0x00007f8deb7486b0 in g_main_context_iteration () from /lib/libglib-2.0.so.0
#80 0x00007f8df1ef31a6 in QEventDispatcherGlib::processEvents (this=0x8bdcb0, flags=<value optimized out>) at kernel/qeventdispatcher_glib.cpp:327
#81 0x00007f8df287f4be in QGuiEventDispatcherGlib::processEvents (this=0x3, flags=<value optimized out>) at kernel/qguieventdispatcher_glib.cpp:202
#82 0x00007f8df1ec9532 in QEventLoop::processEvents (this=<value optimized out>, flags=) at kernel/qeventloop.cpp:149
#83 0x00007f8df1ec9904 in QEventLoop::exec (this=0x7fffe449e510, flags=) at kernel/qeventloop.cpp:201
#84 0x00007f8df1ecbab9 in QCoreApplication::exec () at kernel/qcoreapplication.cpp:888
#85 0x0000000000403f47 in _start ()

Reported using DrKonqi