Application that crashed: konqueror
Version of the application: 4.3.00 (KDE 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 opened a set of bookmarks using the "Open Folder in Tabs" feature. One of the pages caused a redirect from HTTPS to HTTP, causing an "about to leave secure mode" dialog to come up.  If I click "Continue Loading" soon, things work as expected.  However, if I'm busy in another application and don't dismiss the dialog for a few minutes, Konqueror crashes immediately.

 -- Backtrace:
Application: Konqueror (kdeinit4), signal: Segmentation fault
[KCrash Handler]
#6  0xb787e68d in KIO::Slave::deref () from /usr/lib/libkio.so.5
#7  0xb787ee7c in KIO::Slave::gotInput () from /usr/lib/libkio.so.5
#8  0xb7881303 in KIO::Slave::qt_metacall () from /usr/lib/libkio.so.5
#9  0xb7e301b8 in QMetaObject::activate () from /usr/lib/libQtCore.so.4
#10 0xb7e30e42 in QMetaObject::activate () from /usr/lib/libQtCore.so.4
#11 0xb778b1d7 in KIO::Connection::readyRead () from /usr/lib/libkio.so.5
#12 0xb778cb43 in ?? () from /usr/lib/libkio.so.5
#13 0xb778cf26 in KIO::Connection::qt_metacall () from /usr/lib/libkio.so.5
#14 0xb7e298cb in QMetaCallEvent::placeMetaCall () from /usr/lib/libQtCore.so.4
#15 0xb7e2b3b0 in QObject::event () from /usr/lib/libQtCore.so.4
#16 0xb68dbd3c in QApplicationPrivate::notify_helper () from /usr/lib/libQtGui.so.4
#17 0xb68e403e in QApplication::notify () from /usr/lib/libQtGui.so.4
#18 0xb73ec5cd in KApplication::notify () from /usr/lib/libkdeui.so.5
#19 0xb7e1abcb in QCoreApplication::notifyInternal () from /usr/lib/libQtCore.so.4
#20 0xb7e1b825 in QCoreApplicationPrivate::sendPostedEvents () from /usr/lib/libQtCore.so.4
#21 0xb7e1ba1d in QCoreApplication::sendPostedEvents () from /usr/lib/libQtCore.so.4
#22 0xb7e466af in ?? () from /usr/lib/libQtCore.so.4
#23 0xb648eb88 in g_main_context_dispatch () from /usr/lib/libglib-2.0.so.0
#24 0xb64920eb in ?? () from /usr/lib/libglib-2.0.so.0
#25 0xb6492268 in g_main_context_iteration () from /usr/lib/libglib-2.0.so.0
#26 0xb7e462f8 in QEventDispatcherGlib::processEvents () from /usr/lib/libQtCore.so.4
#27 0xb697da75 in ?? () from /usr/lib/libQtGui.so.4
#28 0xb7e191fa in QEventLoop::processEvents () from /usr/lib/libQtCore.so.4
#29 0xb7e19642 in QEventLoop::exec () from /usr/lib/libQtCore.so.4
#30 0xb7e1bae9 in QCoreApplication::exec () from /usr/lib/libQtCore.so.4
#31 0xb68dbbb7 in QApplication::exec () from /usr/lib/libQtGui.so.4
#32 0xb49d00c8 in kdemain () from /usr/lib/libkdeinit4_konqueror.so
#33 0x0804e27d in _start ()

Reported using DrKonqi