Application that crashed: kontact
Version of the application: 4.3.4
KDE Version: 4.3.4 (KDE 4.3.4)
Qt Version: 4.5.2
Operating System: Linux 2.6.31-18-generic x86_64
Distribution: Ubuntu 9.10

What I was doing when the application crashed:
Several days ago Kontact started to complane about two or more instance of him running on startup.
After closing second instance it crashed.

 -- Backtrace:
Application: Kontact (kontact), signal: Segmentation fault
The current source language is "auto; currently c".
[KCrash Handler]
#5  QListData::begin (this=0x24db420) at /usr/include/qt4/QtCore/qlist.h:90
#6  QList<KMFilter*>::begin (this=0x24db420) at /usr/include/qt4/QtCore/qlist.h:238
#7  KMMainWidget::initializeFilterActions (this=0x24db420) at ../../kmail/kmmainwidget.cpp:4783
#8  0x00007fb831a8dc16 in KMailPart::guiActivateEvent (this=0x14fa300, e=0x7fffbb9e5d80) at ../../kmail/kmail_part.cpp:183
#9  0x00007fb84669f155 in QObject::event (this=0x14fa300, e=0x7fffbb9e5d80) at kernel/qobject.cpp:1142
#10 0x00007fb846fb3efc in QApplicationPrivate::notify_helper (this=0x10b3df0, receiver=0x14fa300, e=0x7fffbb9e5d80) at kernel/qapplication.cpp:4056
#11 0x00007fb846fbb1ce in QApplication::notify (this=0x7fffbb9e6a30, receiver=0x14fa300, e=0x7fffbb9e5d80) at kernel/qapplication.cpp:4021
#12 0x00007fb847beae56 in KApplication::notify (this=0x7fffbb9e6a30, receiver=0x14fa300, event=0x7fffbb9e5d80) at ../../kdeui/kernel/kapplication.cpp:302
#13 0x00007fb84668fc2c in QCoreApplication::notifyInternal (this=0x7fffbb9e6a30, receiver=0x14fa300, event=0x7fffbb9e5d80) at kernel/qcoreapplication.cpp:610
#14 0x00007fb845cad687 in QCoreApplication::sendEvent (this=0x11b17c0, part=0x0) at /usr/include/qt4/QtCore/qcoreapplication.h:213
#15 KParts::MainWindow::createGUI (this=0x11b17c0, part=0x0) at ../../kparts/mainwindow.cpp:99
#16 0x00007fb84855ad9c in ~MainWindow (this=0x11b17c0, __in_chrg=<value optimized out>, __vtt_parm=<value optimized out>) at ../../../kontact/src/mainwindow.cpp:256
#17 0x00007fb84669f11d in QObject::event (this=0x11b17c0, e=0x268b600) at kernel/qobject.cpp:1094
#18 0x00007fb84700215f in QWidget::event (this=0x11b17c0, event=0x1ae4170) at kernel/qwidget.cpp:7946
#19 0x00007fb8473789db in QMainWindow::event (this=0x11b17c0, event=0x1ae4170) at widgets/qmainwindow.cpp:1399
#20 0x00007fb847cf6b33 in KXmlGuiWindow::event (this=0x7fffbb9e5500, ev=0x268b600) at ../../kdeui/xmlgui/kxmlguiwindow.cpp:131
#21 0x00007fb846fb3efc in QApplicationPrivate::notify_helper (this=0x10b3df0, receiver=0x11b17c0, e=0x1ae4170) at kernel/qapplication.cpp:4056
#22 0x00007fb846fbb1ce in QApplication::notify (this=0x7fffbb9e6a30, receiver=0x11b17c0, e=0x1ae4170) at kernel/qapplication.cpp:4021
#23 0x00007fb847beae56 in KApplication::notify (this=0x7fffbb9e6a30, receiver=0x11b17c0, event=0x1ae4170) at ../../kdeui/kernel/kapplication.cpp:302
#24 0x00007fb84668fc2c in QCoreApplication::notifyInternal (this=0x7fffbb9e6a30, receiver=0x11b17c0, event=0x1ae4170) at kernel/qcoreapplication.cpp:610
#25 0x00007fb84669080a in QCoreApplication::sendEvent (receiver=0x0, event_type=<value optimized out>, data=0x1075080) at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:213
#26 QCoreApplicationPrivate::sendPostedEvents (receiver=0x0, event_type=<value optimized out>, data=0x1075080) at kernel/qcoreapplication.cpp:1247
#27 0x00007fb8466b8533 in QCoreApplication::sendPostedEvents (s=<value optimized out>) at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:218
#28 postEventSourceDispatch (s=<value optimized out>) at kernel/qeventdispatcher_glib.cpp:210
#29 0x00007fb83ff09bce in g_main_context_dispatch () from /lib/libglib-2.0.so.0
#30 0x00007fb83ff0d598 in ?? () from /lib/libglib-2.0.so.0
#31 0x00007fb83ff0d6c0 in g_main_context_iteration () from /lib/libglib-2.0.so.0
#32 0x00007fb8466b81a6 in QEventDispatcherGlib::processEvents (this=0x1074cb0, flags=<value optimized out>) at kernel/qeventdispatcher_glib.cpp:327
#33 0x00007fb8470484be in QGuiEventDispatcherGlib::processEvents (this=0x7fffbb9e5500, flags=<value optimized out>) at kernel/qguieventdispatcher_glib.cpp:202
#34 0x00007fb84668e532 in QEventLoop::processEvents (this=<value optimized out>, flags=) at kernel/qeventloop.cpp:149
#35 0x00007fb84668e904 in QEventLoop::exec (this=0x7fffbb9e6970, flags=) at kernel/qeventloop.cpp:201
#36 0x00007fb846690ab9 in QCoreApplication::exec () at kernel/qcoreapplication.cpp:888
#37 0x0000000000403f47 in main (argc=<value optimized out>, argv=<value optimized out>) at ../../../kontact/src/main.cpp:218

Reported using DrKonqi