Application that crashed: kmail
Version of the application: 1.12.0
KDE Version: 4.3.00 (KDE 4.3.0)
Qt Version: 4.5.2
Operating System: Linux 2.6.30-020630-generic i686
Distribution: Ubuntu 9.04

What I was doing when the application crashed:
I opened an attachement (a .diff file) in kompare then kmail freezed (maybe checking for new mail?) and suddenly it crashed.

 -- Backtrace:
Application: KMail (kmail), signal: Segmentation fault
[KCrash Handler]
#6  0xb7544b21 in KMHandleAttachmentCommand::slotStart (this=0x9bf4198) at /build/buildd/kdepim-4.3.0/kmail/kmcommands.cpp:2886
#7  0xb75324e3 in KMHandleAttachmentCommand::qt_metacall (this=0x9bf4198, _c=QMetaObject::InvokeMetaMethod, _id=1, _a=0xbfda0d68)
    at /build/buildd/kdepim-4.3.0/obj-i486-linux-gnu/kmail/kmcommands.moc:2240
#8  0xb5dd71b8 in QMetaObject::activate (sender=0xa011780, from_signal_index=4, to_signal_index=4, argv=0x0) at kernel/qobject.cpp:3113
#9  0xb5dd7e42 in QMetaObject::activate (sender=0xa011780, m=0xb5eb3908, local_signal_index=0, argv=0x0) at kernel/qobject.cpp:3187
#10 0xb5ddcf77 in QSingleShotTimer::timeout (this=0xa011780) at .moc/release-shared/qtimer.moc:76
#11 0xb5ddd09c in QSingleShotTimer::timerEvent (this=0xa011780) at kernel/qtimer.cpp:298
#12 0xb5dd216f in QObject::event (this=0xa011780, e=0xbfda11ec) at kernel/qobject.cpp:1075
#13 0xb604dd3c in QApplicationPrivate::notify_helper (this=0x8c5f640, receiver=0xa011780, e=0xbfda11ec) at kernel/qapplication.cpp:4056
#14 0xb605603e in QApplication::notify (this=0xbfda1508, receiver=0xa011780, e=0xbfda11ec) at kernel/qapplication.cpp:3603
#15 0xb7d625cd in KApplication::notify (this=0xbfda1508, receiver=0xa011780, event=0xbfda11ec) at /build/buildd/kde4libs-4.3.0/kdeui/kernel/kapplication.cpp:302
#16 0xb5dc1bcb in QCoreApplication::notifyInternal (this=0xbfda1508, receiver=0xa011780, event=0xbfda11ec) at kernel/qcoreapplication.cpp:610
#17 0xb5df0d51 in QTimerInfoList::activateTimers (this=0x8c62044) at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:213
#18 0xb5ded3a0 in timerSourceDispatch (source=0x8c62010) at kernel/qeventdispatcher_glib.cpp:165
#19 0xb41c7b88 in g_main_context_dispatch () from /usr/lib/libglib-2.0.so.0
#20 0xb41cb0eb in ?? () from /usr/lib/libglib-2.0.so.0
#21 0xb41cb268 in g_main_context_iteration () from /usr/lib/libglib-2.0.so.0
#22 0xb5ded2f8 in QEventDispatcherGlib::processEvents (this=0x8bb33c8, flags={i = -1076227224}) at kernel/qeventdispatcher_glib.cpp:327
#23 0xb60efa75 in QGuiEventDispatcherGlib::processEvents (this=0x8bb33c8, flags={i = -1076227176}) at kernel/qguieventdispatcher_glib.cpp:202
#24 0xb5dc01fa in QEventLoop::processEvents (this=0xbfda1410, flags={i = -1076227112}) at kernel/qeventloop.cpp:149
#25 0xb5dc0642 in QEventLoop::exec (this=0xbfda1410, flags={i = -1076227048}) at kernel/qeventloop.cpp:201
#26 0xb5dc2ae9 in QCoreApplication::exec () at kernel/qcoreapplication.cpp:888
#27 0xb604dbb7 in QApplication::exec () at kernel/qapplication.cpp:3525
#28 0x0804a7d0 in main (argc=0, argv=0x0) at /build/buildd/kdepim-4.3.0/kmail/main.cpp:146

Reported using DrKonqi