Version:            (using KDE 4.1.96)
Compiler:          gcc (Debian 4.3.2-1.1) 4.3.2  / g++ (Debian 4.3.2-1.1) 4.3.2 
OS:                Linux
Installed from:    Compiled From Sources

Crashes in kmail are rather rare nowadays. This one occurred unexpectedly while deleting a number of messages from a mail box that is not inbox. I tried once again to reproduce it, but failed. However, the stack trace might be of some use to understand the problem which seems related 

Application: KMail (kmail), signal SIGABRT
[Current thread is 0 (LWP 4004)]

Thread 2 (Thread 0xb0e1cb90 (LWP 4084)):
#0  0xffffe410 in __kernel_vsyscall ()
#1  0xb5ef7ab1 in select () from /lib/i686/cmov/libc.so.6
#2  0xb6b6b2df in QProcessManager::run (this=0x806f0f0) at io/qprocess_unix.cpp:301
#3  0xb6a98631 in QThreadPrivate::start (arg=0x806f0f0) at thread/qthread_unix.cpp:185
#4  0xb6a044c0 in start_thread () from /lib/i686/cmov/libpthread.so.0
#5  0xb5eff6de in clone () from /lib/i686/cmov/libc.so.6

Thread 1 (Thread 0xb3f38a10 (LWP 4004)):
[KCrash Handler]
#6  0xffffe410 in __kernel_vsyscall ()
#7  0xb5e4a640 in raise () from /lib/i686/cmov/libc.so.6
#8  0xb5e4c018 in abort () from /lib/i686/cmov/libc.so.6
#9  0xb6a8e9fb in qt_message_output (msgType=QtFatalMsg, 
    buf=0xbfefaac0 "ASSERT: \"dyingMessage->isViewable()\" in file /home/kde-devel/kde/src/KDE/kdepim/kmail/messagelistview/core/model.cpp, line 2931") at global/qglobal.cpp:2102
#10 0xb6a8ea5f in qFatal (msg=0xb6bdad78 "ASSERT: \"%s\" in file %s, line %d") at global/qglobal.cpp:2303
#11 0xb6a8ee81 in qt_assert (assertion=0xb79005c0 "dyingMessage->isViewable()", file=0xb78ffec8 "/home/kde-devel/kde/src/KDE/kdepim/kmail/messagelistview/core/model.cpp", line=2931)
    at global/qglobal.cpp:1872
#12 0xb77f482b in KMail::MessageListView::Core::Model::viewItemJobStepInternalForJobPass1Cleanup (this=0x826d708, job=0x85f3f28, tStart=@0xbfefcce4)
    at /home/kde-devel/kde/src/KDE/kdepim/kmail/messagelistview/core/model.cpp:2931
#13 0xb77f64b8 in KMail::MessageListView::Core::Model::viewItemJobStepInternalForJob (this=0x826d708, job=0x85f3f28, tStart=@0xbfefcce4)
    at /home/kde-devel/kde/src/KDE/kdepim/kmail/messagelistview/core/model.cpp:3311
#14 0xb77f6ee6 in KMail::MessageListView::Core::Model::viewItemJobStepInternal (this=0x826d708) at /home/kde-devel/kde/src/KDE/kdepim/kmail/messagelistview/core/model.cpp:3513
#15 0xb77f7bd4 in KMail::MessageListView::Core::Model::viewItemJobStep (this=0x826d708) at /home/kde-devel/kde/src/KDE/kdepim/kmail/messagelistview/core/model.cpp:3672
#16 0xb733e2e4 in KMail::MessageListView::Core::Model::qt_metacall (this=0x826d708, _c=QMetaObject::InvokeMetaMethod, _id=0, _a=0xbfefcf84)
    at /home/kde-devel/kde/build/KDE/kdepim/kmail/moc_model.cpp:75
#17 0xb6b9c1de in QMetaObject::activate (sender=0x8274d18, from_signal_index=4, to_signal_index=4, argv=0x0) at kernel/qobject.cpp:3028
#18 0xb6b9c66b in QMetaObject::activate (sender=0x8274d18, m=0xb6c33a64, local_signal_index=0, argv=0x0) at kernel/qobject.cpp:3101
#19 0xb6bd9da9 in QTimer::timeout (this=0x8274d18) at .moc/debug-shared/moc_qtimer.cpp:126
#20 0xb6ba631e in QTimer::timerEvent (this=0x8274d18, e=0xbfefd534) at kernel/qtimer.cpp:257
#21 0xb6b9a4d6 in QObject::event (this=0x8274d18, e=0xbfefd534) at kernel/qobject.cpp:1120
#22 0xb61ef479 in QApplicationPrivate::notify_helper (this=0x806b7e8, receiver=0x8274d18, e=0xbfefd534) at kernel/qapplication.cpp:3803
#23 0xb61ef78e in QApplication::notify (this=0xbfefd858, receiver=0x8274d18, e=0xbfefd534) at kernel/qapplication.cpp:3393
#24 0xb7dee183 in KApplication::notify (this=0xbfefd858, receiver=0x8274d18, event=0xbfefd534) at /home/kde-devel/kde/src/KDE/kdelibs/kdeui/kernel/kapplication.cpp:307
#25 0xb6b87b2f in QCoreApplication::notifyInternal (this=0xbfefd858, receiver=0x8274d18, event=0xbfefd534) at kernel/qcoreapplication.cpp:583
#26 0xb6b8b6b1 in QCoreApplication::sendEvent (receiver=0x8274d18, event=0xbfefd534) at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:209
#27 0xb6bb8b67 in QTimerInfoList::activateTimers (this=0x806e92c) at kernel/qeventdispatcher_unix.cpp:557
#28 0xb6bb6478 in timerSourceDispatch (source=0x806e8f8) at kernel/qeventdispatcher_glib.cpp:160
#29 0xb45961b8 in g_main_context_dispatch () from /usr/lib/libglib-2.0.so.0
#30 0xb4599853 in ?? () from /usr/lib/libglib-2.0.so.0
#31 0x0806dc68 in ?? ()
#32 0x00000000 in ?? ()