I forgot to mention that the machine on which this occurs appears to be relatively stable. I only get crashes on occasion with other applications and a recent memtest86+ 1.70 run did not yield any errors (although I realise that does not guarantee anything).

Created attachment 26845 [details]
Backtrace with debugging symbols

Yet another crash, but this time with debugging symbols installed. The call
stack appears to be the same as before, hopefully the extra debugging
information will be useful.

Paste comment #2' bt :

[Thread debugging using libthread_db enabled]
[New Thread 0xb602a6c0 (LWP 6930)]
[KCrash handler]
#6  0xb6bdf442 in QGDict::hashKeyString (this=0xb, key=@0xbf858874)
    at tools/qgdict.cpp:101
#7  0xb6bdf8a1 in QGDict::look_string (this=0xb, key=@0xbf858874, d=0x0, op=0)
    at tools/qgdict.cpp:335
#8  0xb7e43f76 in Kopete::NotifyDataObject::notifyEvent (this=0x832084c, 
    event=@0xbf858874) at /usr/share/qt3/include/qdict.h:74
#9  0xb7e9346a in KNotification::event (mc=0x85ae2b8, message=@0xbf858874, 
    text=@0xbf858854, pixmap=@0xbf858828, widget=0x8535c30, 
    actions=@0xbf85884c, flags=2)
    at /build/buildd/kdenetwork-3.5.9/./kopete/libkopete/knotification.cpp:453
#10 0xb7ed788f in KopeteViewManager::messageAppended (this=0x8116788, 
    msg=@0xbf858a78, manager=0x836a448)
    at /build/buildd/kdenetwork-3.5.9/./kopete/libkopete/private/kopeteviewmanager.cpp:240
#11 0xb7ed7f44 in KopeteViewManager::qt_invoke (this=0x8116788, _id=4, 
    _o=0xbf858940) at ./kopeteviewmanager.moc:125
#12 0xb68e5704 in QObject::activate_signal (this=0x81e6fc0, clist=0x828b9f8, 
    o=0xbf858940) at kernel/qobject.cpp:2359
#13 0xb7e4f57e in Kopete::ChatSessionManager::display (this=0x81e6fc0, 
    t0=@0xbf858a78, t1=0x836a448) at ./kopetechatsessionmanager.moc:234
#14 0xb7e50ae9 in Kopete::ChatSessionManager::qt_emit (this=0x81e6fc0, _id=9, 
    _o=0xbf858a10) at ./kopetechatsessionmanager.moc:276
#15 0xb68e5805 in QObject::activate_signal (this=0x836a448, clist=0x83ba0d8, 
    o=0xbf858a10) at kernel/qobject.cpp:2381
#16 0xb7e5122e in Kopete::ChatSession::messageAppended (this=0x836a448, 
    t0=@0xbf858a78, t1=0x836a448) at ./kopetechatsession.moc:297
#17 0xb7eab2f5 in Kopete::TemporaryKMMCallbackAppendMessageHandler::handleMessage (this=0x86e1f60, event=0x85d2798)
    at /build/buildd/kdenetwork-3.5.9/./kopete/libkopete/kopetechatsession.cpp:211
#18 0xb7e43e4c in Kopete::MessageHandler::handleMessageInternal (
    this=0x86e1f60, event=0x85d2798)
    at /build/buildd/kdenetwork-3.5.9/./kopete/libkopete/kopetemessagehandler.cpp:60
#19 0xb7e44371 in Kopete::MessageHandler::messageAccepted (this=0x869efa8, 
    event=0x85d2798)
    at /build/buildd/kdenetwork-3.5.9/./kopete/libkopete/kopetemessagehandler.cpp:71
#20 0xb7e443a4 in Kopete::MessageHandler::handleMessage (this=0x869efa8, 
    event=0x85d2798)
    at /build/buildd/kdenetwork-3.5.9/./kopete/libkopete/kopetemessagehandler.cpp:65
#21 0xb5846428 in HistoryMessageLogger::handleMessage (this=0x869efa8, 
    event=0x85d2798)
    at /build/buildd/kdenetwork-3.5.9/./kopete/plugins/history/historyplugin.cpp:97
#22 0xb7e43e4c in Kopete::MessageHandler::handleMessageInternal (
    this=0x869efa8, event=0x85d2798)
    at /build/buildd/kdenetwork-3.5.9/./kopete/libkopete/kopetemessagehandler.cpp:60
#23 0xb7e47dce in Kopete::ProcessMessageTask::slotStart (this=0x8749480)
    at /build/buildd/kdenetwork-3.5.9/./kopete/libkopete/kopetemessagehandlerchain.cpp:166
#24 0xb7e50233 in Kopete::ProcessMessageTask::qt_invoke (this=0x8749480, 
    _id=5, _o=0xbf858c18) at ./kopetemessagehandlerchain.moc:159
#25 0xb68e5704 in QObject::activate_signal (this=0x81e8730, clist=0x8676068, 
    o=0xbf858c18) at kernel/qobject.cpp:2359
#26 0xb6c74aba in QSignal::signal (this=0x81e8730, t0=@0x81e8758)
    at .moc/debug-shared-mt/moc_qsignal.cpp:100
#27 0xb69047b2 in QSignal::activate (this=0x81e8730) at kernel/qsignal.cpp:215
#28 0xb690c936 in QSingleShotTimer::event (this=0x81e8708)
    at kernel/qtimer.cpp:289
#29 0xb6879c36 in QApplication::internalNotify (this=0xbf8591f4, 
    receiver=0x81e8708, e=0xbf858f28) at kernel/qapplication.cpp:2638
#30 0xb687ba5f in QApplication::notify (this=0xbf8591f4, receiver=0x81e8708, 
    e=0xbf858f28) at kernel/qapplication.cpp:2361
#31 0xb703a672 in KApplication::notify (this=0xbf8591f4, receiver=0x81e8708, 
    event=0xbf858f28)
    at /build/buildd/kdelibs-3.5.9/./kdecore/kapplication.cpp:550
#32 0xb680a28d in QApplication::sendEvent (receiver=0x81e8708, 
    event=0xbf858f28) at ../include/qapplication.h:523
#33 0xb686cb19 in QEventLoop::activateTimers (this=0x8163178)
    at kernel/qeventloop_unix.cpp:559
#34 0xb681f64b in QEventLoop::processEvents (this=0x8163178, flags=4)
    at kernel/qeventloop_x11.cpp:392
#35 0xb6894f90 in QEventLoop::enterLoop (this=0x8163178)
    at kernel/qeventloop.cpp:201
#36 0xb6894c8e in QEventLoop::exec (this=0x8163178)
    at kernel/qeventloop.cpp:148
#37 0xb687b7df in QApplication::exec (this=0xbf8591f4)
    at kernel/qapplication.cpp:2761
#38 0x0807fc73 in main (argc=135311552, argv=0x81bbd10)
    at /build/buildd/kdenetwork-3.5.9/./kopete/kopete/main.cpp:107

Just writing to say that the crashes are still happening, and to confirm that they still follow the same pattern, albeit with different memory addresses.

I have had Kopete running continuously without crashing for over 32 hours now (and it's still going!), ever since I blocked all MSN users other than those already in my list. Hence, I have not had to delete any spammers from my contact list, leading me to suspect that this may be a cause for the repeated crashing I have experienced. I do not know if the crash is specific or limited to the MSN plug-in, however.

We've substantially updated the MSN code with KDE 4.2 Beta 1. If you can reproduce with that version, please reopen the bug.