Application that crashed: kontact
Version of the application: 4.3.0
KDE Version: 4.3.00 (KDE 4.3.0)
Qt Version: 4.5.2
Operating System: Linux 2.6.28-15-generic i686
Distribution: Ubuntu 9.04

What I was doing when the application crashed:
I start Kontact via the main menu. The first window is from Kmail and when I click on summary the application crashes for an unknown reason.

 -- Backtrace:
Application: Kontact (kontact), signal: Segmentation fault
[Current thread is 0 (LWP 13221)]

Thread 2 (Thread 0xb01d0b90 (LWP 13226)):
#0  0xb80ca430 in __kernel_vsyscall ()
#1  0xb525a412 in pthread_cond_timedwait@@GLIBC_2.3.2 () from /lib/tls/i686/cmov/libpthread.so.0
#2  0xb5a7b344 in pthread_cond_timedwait () from /lib/tls/i686/cmov/libc.so.6
#3  0xb5c5f14c in QWaitCondition::wait () from /usr/lib/libQtCore.so.4
#4  0xb5c53ac6 in ?? () from /usr/lib/libQtCore.so.4
#5  0xb5c5e132 in ?? () from /usr/lib/libQtCore.so.4
#6  0xb52564ff in start_thread () from /lib/tls/i686/cmov/libpthread.so.0
#7  0xb5a6c49e in clone () from /lib/tls/i686/cmov/libc.so.6

Thread 1 (Thread 0xb496eb30 (LWP 13221)):
[KCrash Handler]
#5  0xb5ca2efa in QString::operator== () from /usr/lib/libQtCore.so.4
#6  0xb746f2e7 in KCal::ResourceCached::clearChange () from /usr/lib/libkcal.so.4
#7  0xb746f67b in KCal::ResourceCached::clearChange () from /usr/lib/libkcal.so.4
#8  0xaaf60344 in KCal::ResourceRemote::slotSaveJobResult () from /usr/lib/libkcal_resourceremote.so.4
#9  0xaaf60857 in KCal::ResourceRemote::qt_metacall () from /usr/lib/libkcal_resourceremote.so.4
#10 0xb5d681b8 in QMetaObject::activate () from /usr/lib/libQtCore.so.4
#11 0xb5d68e42 in QMetaObject::activate () from /usr/lib/libQtCore.so.4
#12 0xb5f8ecb3 in KJob::result () from /usr/lib/libkdecore.so.5
#13 0xb5f8f159 in KJob::emitResult () from /usr/lib/libkdecore.so.5
#14 0xb708e6b8 in KIO::FileCopyJob::slotResult () from /usr/lib/libkio.so.5
#15 0xb708921f in KIO::FileCopyJob::qt_metacall () from /usr/lib/libkio.so.5
#16 0xb5d681b8 in QMetaObject::activate () from /usr/lib/libQtCore.so.4
#17 0xb5d68e42 in QMetaObject::activate () from /usr/lib/libQtCore.so.4
#18 0xb5f8ecb3 in KJob::result () from /usr/lib/libkdecore.so.5
#19 0xb5f8f159 in KJob::emitResult () from /usr/lib/libkdecore.so.5
#20 0xb7089c25 in KIO::SimpleJob::slotFinished () from /usr/lib/libkio.so.5
#21 0xb708a563 in KIO::TransferJob::slotFinished () from /usr/lib/libkio.so.5
#22 0xb7086b0b in KIO::TransferJob::qt_metacall () from /usr/lib/libkio.so.5
#23 0xb5d681b8 in QMetaObject::activate () from /usr/lib/libQtCore.so.4
#24 0xb5d68e42 in QMetaObject::activate () from /usr/lib/libQtCore.so.4
#25 0xb714fc17 in KIO::SlaveInterface::finished () from /usr/lib/libkio.so.5
#26 0xb7153957 in KIO::SlaveInterface::dispatch () from /usr/lib/libkio.so.5
#27 0xb71500f7 in KIO::SlaveInterface::dispatch () from /usr/lib/libkio.so.5
#28 0xb7141e6d in KIO::Slave::gotInput () from /usr/lib/libkio.so.5
#29 0xb7144303 in KIO::Slave::qt_metacall () from /usr/lib/libkio.so.5
#30 0xb5d681b8 in QMetaObject::activate () from /usr/lib/libQtCore.so.4
#31 0xb5d68e42 in QMetaObject::activate () from /usr/lib/libQtCore.so.4
#32 0xb704e1d7 in KIO::Connection::readyRead () from /usr/lib/libkio.so.5
#33 0xb704fb43 in ?? () from /usr/lib/libkio.so.5
#34 0xb704ff26 in KIO::Connection::qt_metacall () from /usr/lib/libkio.so.5
#35 0xb5d618cb in QMetaCallEvent::placeMetaCall () from /usr/lib/libQtCore.so.4
#36 0xb5d633b0 in QObject::event () from /usr/lib/libQtCore.so.4
#37 0xb6213d3c in QApplicationPrivate::notify_helper () from /usr/lib/libQtGui.so.4
#38 0xb621c03e in QApplication::notify () from /usr/lib/libQtGui.so.4
#39 0xb6e0d5cd in KApplication::notify () from /usr/lib/libkdeui.so.5
#40 0xb5d52bcb in QCoreApplication::notifyInternal () from /usr/lib/libQtCore.so.4
#41 0xb5d53825 in QCoreApplicationPrivate::sendPostedEvents () from /usr/lib/libQtCore.so.4
#42 0xb5d53a1d in QCoreApplication::sendPostedEvents () from /usr/lib/libQtCore.so.4
#43 0xb5d7e6af in ?? () from /usr/lib/libQtCore.so.4
#44 0xb4e24b88 in g_main_context_dispatch () from /usr/lib/libglib-2.0.so.0
#45 0xb4e280eb in ?? () from /usr/lib/libglib-2.0.so.0
#46 0xb4e28268 in g_main_context_iteration () from /usr/lib/libglib-2.0.so.0
#47 0xb5d7e2f8 in QEventDispatcherGlib::processEvents () from /usr/lib/libQtCore.so.4
#48 0xb62b5a75 in ?? () from /usr/lib/libQtGui.so.4
#49 0xb5d511fa in QEventLoop::processEvents () from /usr/lib/libQtCore.so.4
#50 0xb5d51642 in QEventLoop::exec () from /usr/lib/libQtCore.so.4
#51 0xb5d53ae9 in QCoreApplication::exec () from /usr/lib/libQtCore.so.4
#52 0xb6213bb7 in QApplication::exec () from /usr/lib/libQtGui.so.4
#53 0x0804bfef in _start ()

Reported using DrKonqi