Version:            (using Devel)
OS:                Linux
Installed from:    Compiled sources

I have an overdue todo item in my calendar. If I'm trying to open the Calendar Application either from the sidebar icon or from the overview page Kontact crashes.
Opening KOrganizer without Kontact running doesn't result in a crash.

Here is the backtrace:

Anwendung: Kontact (kontact), Signal SIGSEGV
[?1034h[Thread debugging using libthread_db enabled]
[Current thread is 1 (Thread 0xb49aa700 (LWP 7522))]

Thread 2 (Thread 0xaf226b90 (LWP 7551)):
#0  0xffffe430 in __kernel_vsyscall ()
#1  0xb5a473e1 in select () from /lib/libc.so.6
#2  0xb676bdc7 in ?? () from /usr/lib/libQtCore.so.4
#3  0xb669c85e in ?? () from /usr/lib/libQtCore.so.4
#4  0xb66391b5 in start_thread () from /lib/libpthread.so.0
#5  0xb5a4e38e in clone () from /lib/libc.so.6

Thread 1 (Thread 0xb49aa700 (LWP 7522)):
[KCrash Handler]
#6  0xb66a7ff7 in QDate::isValid() const () from /usr/lib/libQtCore.so.4
#7  0xb6977ef3 in KDateTime::isValid (this=0xbfc40398) at /usr/src/debug/kdelibs-4.1.96/kdecore/date/kdatetime.cpp:825
#8  0xb733de6f in KCal::Todo::isOverdue (this=0x9927550) at /usr/src/debug/kdepimlibs-4.1.96/kcal/todo.cpp:481
#9  0xac138990 in KOTodoModel::data (this=0x120ce9e8, index=@0xbfc404ec, role=8) at /usr/src/debug/kdepim-4.1.96/korganizer/views/todoview/kotodomodel.cpp:685
#10 0xb626cb9e in QSortFilterProxyModel::data(QModelIndex const&, int) const () from /usr/lib/libQtGui.so.4
#11 0xb6291432 in QStyledItemDelegate::initStyleOption(QStyleOptionViewItem*, QModelIndex const&) const () from /usr/lib/libQtGui.so.4
#12 0xb62922b4 in QStyledItemDelegate::sizeHint(QStyleOptionViewItem const&, QModelIndex const&) const () from /usr/lib/libQtGui.so.4
#13 0xac140044 in KOTodoRichTextDelegate::sizeHint (this=0x117ed9c8, option=@0xbfc407d4, index=@0xbfc40854) at /usr/src/debug/kdepim-4.1.96/korganizer/views/todoview/kotododelegates.cpp:465
#14 0xb62239d9 in QTreeView::indexRowSizeHint(QModelIndex const&) const () from /usr/lib/libQtGui.so.4
#15 0xb6223d52 in ?? () from /usr/lib/libQtGui.so.4
#16 0xb6224010 in ?? () from /usr/lib/libQtGui.so.4
#17 0xb6224392 in QTreeView::updateGeometries() () from /usr/lib/libQtGui.so.4
#18 0xb61e3359 in QAbstractItemView::doItemsLayout() () from /usr/lib/libQtGui.so.4
#19 0xb622fa2a in QTreeView::doItemsLayout() () from /usr/lib/libQtGui.so.4
#20 0xb61edbd1 in QAbstractItemView::timerEvent(QTimerEvent*) () from /usr/lib/libQtGui.so.4
#21 0xb622e80b in QTreeView::timerEvent(QTimerEvent*) () from /usr/lib/libQtGui.so.4
#22 0xb679c04f in QObject::event(QEvent*) () from /usr/lib/libQtCore.so.4
#23 0xb5d79104 in QWidget::event(QEvent*) () from /usr/lib/libQtGui.so.4
#24 0xb60afa83 in QFrame::event(QEvent*) () from /usr/lib/libQtGui.so.4
#25 0xb6146c8d in QAbstractScrollArea::event(QEvent*) () from /usr/lib/libQtGui.so.4
#26 0xb61e3ebc in QAbstractItemView::event(QEvent*) () from /usr/lib/libQtGui.so.4
#27 0xb5d218fc in QApplicationPrivate::notify_helper(QObject*, QEvent*) () from /usr/lib/libQtGui.so.4
#28 0xb5d2982a in QApplication::notify(QObject*, QEvent*) () from /usr/lib/libQtGui.so.4
#29 0xb6d298fd in KApplication::notify (this=0xbfc42fb8, receiver=0xf937108, event=0xbfc41140) at /usr/src/debug/kdelibs-4.1.96/kdeui/kernel/kapplication.cpp:307
#30 0xb678c961 in QCoreApplication::notifyInternal(QObject*, QEvent*) () from /usr/lib/libQtCore.so.4
#31 0xb67bab86 in ?? () from /usr/lib/libQtCore.so.4
#32 0xb67b7060 in ?? () from /usr/lib/libQtCore.so.4
#33 0xb51369a8 in g_main_context_dispatch () from /usr/lib/libglib-2.0.so.0
#34 0xb513a063 in ?? () from /usr/lib/libglib-2.0.so.0
#35 0xb513a221 in g_main_context_iteration () from /usr/lib/libglib-2.0.so.0
#36 0xb67b6fb8 in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/libQtCore.so.4
#37 0xb5dba785 in ?? () from /usr/lib/libQtGui.so.4
#38 0xb678b01a in QEventLoop::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/libQtCore.so.4
#39 0xb678b1da in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/libQtCore.so.4
#40 0xb69ac251 in KJob::exec (this=0x98ae4b0) at /usr/src/debug/kdelibs-4.1.96/kdecore/jobs/kjob.cpp:195
#41 0xb0440e22 in KCal::ResourceAkonadi::Private::reloadSubResource (this=0x96addf0, subResource=0x88739b8, changed=@0xbfc415bb)
    at /usr/src/debug/kdepim-4.1.96/kresources/akonadi/kcal/resourceakonadi.cpp:1455
#42 0xb0443356 in KCal::ResourceAkonadi::doLoad (this=0x96ad608, syncCache=false) at /usr/src/debug/kdepim-4.1.96/kresources/akonadi/kcal/resourceakonadi.cpp:703
#43 0xb73a42ed in KCal::ResourceCalendar::load (this=0x96ad608) at /usr/src/debug/kdepimlibs-4.1.96/kcal/resourcecalendar.cpp:168
#44 0xb73b65d1 in KCal::CalendarResources::load (this=0x87f4038) at /usr/src/debug/kdepimlibs-4.1.96/kcal/calendarresources.cpp:272
#45 0xae730913 in KOrganizerPart (this=0xf98ffb8, parentWidget=0x814f490, parent=0x814f490) at /usr/src/debug/kdepim-4.1.96/korganizer/korganizer_part.cpp:88
#46 0xae7313e2 in KPluginFactory::createPartInstance<KOrganizerPart> (parentWidget=0x814f490, parent=0x814f490, args=@0xbfc41840) at /usr/include/kpluginfactory.h:467
#47 0xb6aa68ef in KPluginFactory::create (this=0x11ec23b8, iface=0xb71c1aa0 "KParts::ReadOnlyPart", parentWidget=0x814f490, parent=0x814f490, args=@0xbfc41840, keyword=@0xbfc41830)
    at /usr/src/debug/kdelibs-4.1.96/kdecore/util/kpluginfactory.cpp:191
#48 0xb78c8c72 in Kontact::Core::createPart (this=0x814f490, libname=0x8272b90 "korganizerpart") at /usr/include/kpluginfactory.h:491
#49 0xb78ca237 in Kontact::Plugin::loadPart (this=0x82004f8) at /usr/src/debug/kdepim-4.1.96/kontactinterfaces/plugin.cpp:148
#50 0xb16a8be5 in KOrganizerPlugin::createPart (this=0x82004f8) at /usr/src/debug/kdepim-4.1.96/kontact/plugins/korganizer/korganizerplugin.cpp:91
#51 0xb78ca192 in Kontact::Plugin::part (this=0x82004f8) at /usr/src/debug/kdepim-4.1.96/kontactinterfaces/plugin.cpp:187
#52 0xb78e9228 in Kontact::MainWindow::selectPlugin (this=0x814f490, plugin=0x82004f8) at /usr/src/debug/kdepim-4.1.96/kontact/src/mainwindow.cpp:752
#53 0xb78e90b4 in Kontact::MainWindow::qt_metacall (this=0x814f490, _c=QMetaObject::InvokeMetaMethod, _id=0, _a=0xbfc41bdc) at /usr/src/debug/kdepim-4.1.96/build/kontact/src/mainwindow.moc:106
#54 0xb67a1580 in QMetaObject::activate(QObject*, int, int, void**) () from /usr/lib/libQtCore.so.4
#55 0xb67a2302 in QMetaObject::activate(QObject*, QMetaObject const*, int, void**) () from /usr/lib/libQtCore.so.4
#56 0xb78eba23 in Kontact::SidePaneBase::pluginSelected (this=0x81417d0, _t1=0x82004f8) at /usr/src/debug/kdepim-4.1.96/build/kontact/src/sidepanebase.moc:82
#57 0xb78ebabf in Kontact::SidePaneBase::qt_metacall (this=0x81417d0, _c=QMetaObject::InvokeMetaMethod, _id=0, _a=0xbfc41d0c) at /usr/src/debug/kdepim-4.1.96/build/kontact/src/sidepanebase.moc:70
#58 0xb78ebd6a in Kontact::IconSidePane::qt_metacall (this=0x81417d0, _c=QMetaObject::InvokeMetaMethod, _id=27, _a=0xbfc41d0c) at /usr/src/debug/kdepim-4.1.96/build/kontact/src/iconsidepane.moc:130
#59 0xb67a1580 in QMetaObject::activate(QObject*, int, int, void**) () from /usr/lib/libQtCore.so.4
#60 0xb67a2302 in QMetaObject::activate(QObject*, QMetaObject const*, int, void**) () from /usr/lib/libQtCore.so.4
#61 0xb78ebe53 in Kontact::Navigator::pluginActivated (this=0x807da38, _t1=0x82004f8) at /usr/src/debug/kdepim-4.1.96/build/kontact/src/iconsidepane.moc:88
#62 0xb78ec7fd in Kontact::Navigator::qt_metacall (this=0x807da38, _c=QMetaObject::InvokeMetaMethod, _id=1, _a=0xbfc41e08) at /usr/src/debug/kdepim-4.1.96/build/kontact/src/iconsidepane.moc:75
#63 0xb67a1580 in QMetaObject::activate(QObject*, int, int, void**) () from /usr/lib/libQtCore.so.4
#64 0xb67a2302 in QMetaObject::activate(QObject*, QMetaObject const*, int, void**) () from /usr/lib/libQtCore.so.4
#65 0xb6238779 in QItemSelectionModel::currentChanged(QModelIndex const&, QModelIndex const&) () from /usr/lib/libQtGui.so.4
#66 0xb623891d in QItemSelectionModel::setCurrentIndex(QModelIndex const&, QFlags<QItemSelectionModel::SelectionFlag>) () from /usr/lib/libQtGui.so.4
#67 0xb61ea93a in QAbstractItemView::mousePressEvent(QMouseEvent*) () from /usr/lib/libQtGui.so.4
#68 0xb5d79a49 in QWidget::event(QEvent*) () from /usr/lib/libQtGui.so.4
#69 0xb60afa83 in QFrame::event(QEvent*) () from /usr/lib/libQtGui.so.4
#70 0xb61461bf in QAbstractScrollArea::viewportEvent(QEvent*) () from /usr/lib/libQtGui.so.4
#71 0xb61f0f3f in QAbstractItemView::viewportEvent(QEvent*) () from /usr/lib/libQtGui.so.4
#72 0xb6148765 in ?? () from /usr/lib/libQtGui.so.4
#73 0xb678bb3a in QCoreApplicationPrivate::sendThroughObjectEventFilters(QObject*, QEvent*) () from /usr/lib/libQtCore.so.4
#74 0xb5d218da in QApplicationPrivate::notify_helper(QObject*, QEvent*) () from /usr/lib/libQtGui.so.4
#75 0xb5d2a111 in QApplication::notify(QObject*, QEvent*) () from /usr/lib/libQtGui.so.4
#76 0xb6d298fd in KApplication::notify (this=0xbfc42fb8, receiver=0x80611e8, event=0xbfc426e8) at /usr/src/debug/kdelibs-4.1.96/kdeui/kernel/kapplication.cpp:307
#77 0xb678c961 in QCoreApplication::notifyInternal(QObject*, QEvent*) () from /usr/lib/libQtCore.so.4
#78 0xb5d2939e in QApplicationPrivate::sendMouseEvent(QWidget*, QMouseEvent*, QWidget*, QWidget*, QWidget**, QPointer<QWidget>&) () from /usr/lib/libQtGui.so.4
#79 0xb5d93716 in ?? () from /usr/lib/libQtGui.so.4
#80 0xb5d92ac5 in QApplication::x11ProcessEvent(_XEvent*) () from /usr/lib/libQtGui.so.4
#81 0xb5dbb08a in ?? () from /usr/lib/libQtGui.so.4
#82 0xb51369a8 in g_main_context_dispatch () from /usr/lib/libglib-2.0.so.0
#83 0xb513a063 in ?? () from /usr/lib/libglib-2.0.so.0
#84 0xb513a221 in g_main_context_iteration () from /usr/lib/libglib-2.0.so.0
#85 0xb67b6fb8 in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/libQtCore.so.4
#86 0xb5dba785 in ?? () from /usr/lib/libQtGui.so.4
#87 0xb678b01a in QEventLoop::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/libQtCore.so.4
#88 0xb678b1da in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/libQtCore.so.4
#89 0xb678d895 in QCoreApplication::exec() () from /usr/lib/libQtCore.so.4
#90 0xb5d21777 in QApplication::exec() () from /usr/lib/libQtGui.so.4
#91 0x0804bf8f in main (argc=1, argv=0xbfc432b4) at /usr/src/debug/kdepim-4.1.96/kontact/src/main.cpp:218

Hope that helps. Thank you!