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 2.6.31-18-generic i686
Distribution: Ubuntu 9.10

What I was doing when the application crashed:
while deleting single mails with the delete key within a subfolder of kontact the program chrashed immediately. 

 -- Backtrace:
Application: Kontact (kontact), signal: Segmentation fault
[KCrash Handler]
#6  DwString::data (aStr=..., aCstr=0x8d788e8 "Message-Id") at ../../mimelib/mimelib/string.h:627
#7  DwStrcasecmp (aStr=..., aCstr=0x8d788e8 "Message-Id") at ../../mimelib/dwstring.cpp:1771
#8  0x030667c2 in DwHeaders::FindField (this=0x8b45e98, aFieldName=0x8d788e8 "Message-Id") at ../../mimelib/headers.cpp:289
#9  0xb4365496 in KMMessage::headerField (this=0x8e84ad8, aName=..., encodingMode=KMMessage::MessageCharsetEncoding) at ../../kmail/kmmessage.cpp:1990
#10 0xb43694c7 in KMMessage::msgId (this=0x8e84ad8) at ../../kmail/kmmessage.cpp:1888
#11 0xb447dffc in KMReaderWin::parseMsg (this=0x86b7860, aMsg=0x8e84ad8) at ../../kmail/kmreaderwin.cpp:1758
#12 0xb446b4d9 in KMReaderWin::displayMessage (this=0x86b7860) at ../../kmail/kmreaderwin.cpp:1605
#13 0xb446b6cb in KMReaderWin::updateReaderWin (this=0x86b7860) at ../../kmail/kmreaderwin.cpp:1545
#14 0xb44789d4 in KMReaderWin::qt_metacall (this=0x86b7860, _c=QMetaObject::InvokeMetaMethod, _id=6, _a=0xbfb2f71c) at ./kmreaderwin.moc:168
#15 0x00a61263 in QMetaObject::activate (sender=0x86b78b8, from_signal_index=4, to_signal_index=4, argv=0x0) at kernel/qobject.cpp:3113
#16 0x00a61ec2 in QMetaObject::activate (sender=0x86b78b8, m=0xb3c904, local_signal_index=0, argv=0x0) at kernel/qobject.cpp:3187
#17 0x00a9b667 in QTimer::timeout (this=0x86b78b8) at .moc/release-shared/moc_qtimer.cpp:128
#18 0x00a669ae in QTimer::timerEvent (this=0x86b78b8, e=0xbfb2fbb0) at kernel/qtimer.cpp:261
#19 0x00a5b3bf in QObject::event (this=0x86b78b8, e=0xbfb2fbb0) at kernel/qobject.cpp:1075
#20 0x01090f54 in QApplicationPrivate::notify_helper (this=0x81cbbf8, receiver=0x86b78b8, e=0xbfb2fbb0) at kernel/qapplication.cpp:4056
#21 0x0109867c in QApplication::notify (this=0xbfb2ff14, receiver=0x86b78b8, e=0xbfb2fbb0) at kernel/qapplication.cpp:3603
#22 0x002e2bfa in KApplication::notify (this=0xbfb2ff14, receiver=0x86b78b8, event=0xbfb2fbb0) at ../../kdeui/kernel/kapplication.cpp:302
#23 0x00a4b6cb in QCoreApplication::notifyInternal (this=0xbfb2ff14, receiver=0x86b78b8, event=0xbfb2fbb0) at kernel/qcoreapplication.cpp:610
#24 0x00a787ce in QCoreApplication::sendEvent (this=0x81c336c) at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:213
#25 QTimerInfoList::activateTimers (this=0x81c336c) at kernel/qeventdispatcher_unix.cpp:572
#26 0x00a760e0 in timerSourceDispatch (source=0x81c3338) at kernel/qeventdispatcher_glib.cpp:165
#27 0x01ff9e88 in g_main_context_dispatch () from /lib/libglib-2.0.so.0
#28 0x01ffd730 in ?? () from /lib/libglib-2.0.so.0
#29 0x01ffd863 in g_main_context_iteration () from /lib/libglib-2.0.so.0
#30 0x00a7602c in QEventDispatcherGlib::processEvents (this=0x81bead8, flags=...) at kernel/qeventdispatcher_glib.cpp:327
#31 0x01131be5 in QGuiEventDispatcherGlib::processEvents (this=0x81bead8, flags=...) at kernel/qguieventdispatcher_glib.cpp:202
#32 0x00a49c79 in QEventLoop::processEvents (this=0xbfb2fe74, flags=) at kernel/qeventloop.cpp:149
#33 0x00a4a0ca in QEventLoop::exec (this=0xbfb2fe74, flags=...) at kernel/qeventloop.cpp:201
#34 0x00a4c53f in QCoreApplication::exec () at kernel/qcoreapplication.cpp:888
#35 0x01090dd7 in QApplication::exec () at kernel/qapplication.cpp:3525
#36 0x0804b4e6 in main (argc=1, argv=0xbfb30134) at ../../../kontact/src/main.cpp:218

Reported using DrKonqi