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:
kontact is crashing after kmail is trying to download mails from POP3 account and it shows "Unable to complete LIST operation"

 -- Backtrace:
Application: Kontact (kontact), signal: Segmentation fault
[KCrash Handler]
#5  0x00007f3966355758 in KIO::Slave::deref() () from /usr/lib/libkio.so.5
#6  0x00007f3966356159 in KIO::Slave::gotInput() () from /usr/lib/libkio.so.5
#7  0x00007f396635826c in KIO::Slave::qt_metacall(QMetaObject::Call, int, void**) () from /usr/lib/libkio.so.5
#8  0x00007f3967e46ddc in QMetaObject::activate(QObject*, int, int, void**) () from /usr/lib/libQtCore.so.4
#9  0x00007f3966272f57 in ?? () from /usr/lib/libkio.so.5
#10 0x00007f396627307d in KIO::Connection::qt_metacall(QMetaObject::Call, int, void**) () from /usr/lib/libkio.so.5
#11 0x00007f3967e410f9 in QObject::event(QEvent*) () from /usr/lib/libQtCore.so.4
#12 0x00007f3968751efc in QApplicationPrivate::notify_helper(QObject*, QEvent*) () from /usr/lib/libQtGui.so.4
#13 0x00007f39687591ce in QApplication::notify(QObject*, QEvent*) () from /usr/lib/libQtGui.so.4
#14 0x00007f3969388ab6 in KApplication::notify(QObject*, QEvent*) () from /usr/lib/libkdeui.so.5
#15 0x00007f3967e31c2c in QCoreApplication::notifyInternal(QObject*, QEvent*) () from /usr/lib/libQtCore.so.4
#16 0x00007f3967e3280a in QCoreApplicationPrivate::sendPostedEvents(QObject*, int, QThreadData*) () from /usr/lib/libQtCore.so.4
#17 0x00007f3967e5a533 in ?? () from /usr/lib/libQtCore.so.4
#18 0x00007f39616acbce in g_main_context_dispatch () from /lib/libglib-2.0.so.0
#19 0x00007f39616b0598 in ?? () from /lib/libglib-2.0.so.0
#20 0x00007f39616b06c0 in g_main_context_iteration () from /lib/libglib-2.0.so.0
#21 0x00007f3967e5a1a6 in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/libQtCore.so.4
#22 0x00007f39687e64be in ?? () from /usr/lib/libQtGui.so.4
#23 0x00007f3967e30532 in QEventLoop::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/libQtCore.so.4
#24 0x00007f3967e30904 in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/libQtCore.so.4
#25 0x00007f3967e32ab9 in QCoreApplication::exec() () from /usr/lib/libQtCore.so.4
#26 0x0000000000403f47 in _start ()

Reported using DrKonqi