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 2.6.31-20-generic x86_64
Distribution: Ubuntu 9.10

What I was doing when the application crashed:
I started Kontact, Kmail searches new mails, I choose Kmail after that kontact crashed.

 -- Backtrace:
Application: Kontact (kontact), signal: Segmentation fault
[KCrash Handler]
#5  0x00007ff1f4a27fdc in QApplication::notify(QObject*, QEvent*) () from /usr/lib/libQtGui.so.4
#6  0x00007ff1f5657ab6 in KApplication::notify(QObject*, QEvent*) () from /usr/lib/libkdeui.so.5
#7  0x00007ff1f4100c2c in QCoreApplication::notifyInternal(QObject*, QEvent*) () from /usr/lib/libQtCore.so.4
#8  0x00007ff1f4a278e0 in QApplicationPrivate::sendMouseEvent(QWidget*, QMouseEvent*, QWidget*, QWidget*, QWidget**, QPointer<QWidget>&) () from /usr/lib/libQtGui.so.4
#9  0x00007ff1f4a8da0e in ?? () from /usr/lib/libQtGui.so.4
#10 0x00007ff1f4a8caa9 in QApplication::x11ProcessEvent(_XEvent*) () from /usr/lib/libQtGui.so.4
#11 0x00007ff1f4ab5d0c in ?? () from /usr/lib/libQtGui.so.4
#12 0x00007ff1ed97bbce in g_main_context_dispatch () from /lib/libglib-2.0.so.0
#13 0x00007ff1ed97f598 in ?? () from /lib/libglib-2.0.so.0
#14 0x00007ff1ed97f6c0 in g_main_context_iteration () from /lib/libglib-2.0.so.0
#15 0x00007ff1f41291a6 in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/libQtCore.so.4
#16 0x00007ff1f4ab54be in ?? () from /usr/lib/libQtGui.so.4
#17 0x00007ff1f40ff532 in QEventLoop::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/libQtCore.so.4
#18 0x00007ff1f40ff904 in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/libQtCore.so.4
#19 0x00007ff1f4101ab9 in QCoreApplication::exec() () from /usr/lib/libQtCore.so.4
#20 0x0000000000403f47 in _start ()

Reported using DrKonqi