Version:           1.11.0 (using 4.1.96 (KDE 4.1.96 (KDE 4.2 RC1)) "release 78.1", KDE:KDE4:Factory:Desktop / openSUSE_11.1)
Compiler:          gcc
OS:                Linux (x86_64) release 2.6.27.7-9-default

kmail crashes frequently 
IMHO an index issue because it does not crash if the index and directory files are removed.
hope that the BT is of some help

This backtrace appears to be of no use.
This is probably because your packages are built in a way which prevents creation of proper backtraces, or the stack frame was seriously corrupted in the crash.

[?1034h(no debugging symbols found)
(no debugging symbols found)
(no debugging symbols found)
(no debugging symbols found)
(no debugging symbols found)
[Thread debugging using libthread_db enabled]
[New Thread 0x7f7038613950 (LWP 14296)]
(no debugging symbols found)
(no debugging symbols found)
(no debugging symbols found)
(no debugging symbols found)
(no debugging symbols found)
0x00007f704d4f1ce1 in nanosleep () from /lib64/libc.so.6
[Current thread is 1 (Thread 0x7f70529fe750 (LWP 14295))]

Thread 2 (Thread 0x7f7038613950 (LWP 14296)):
#0  0x00007f704ef8bfdd in pthread_cond_timedwait@@GLIBC_2.3.2 () from /lib64/libpthread.so.0
#1  0x00007f704f1fcf07 in QWaitCondition::wait(QMutex*, unsigned long) () from /usr/lib64/libQtCore.so.4
#2  0x00007f704f1f3129 in ?? () from /usr/lib64/libQtCore.so.4
#3  0x00007f704f1fbf72 in ?? () from /usr/lib64/libQtCore.so.4
#4  0x00007f704ef88070 in start_thread () from /lib64/libpthread.so.0
#5  0x00007f704d5230ed in clone () from /lib64/libc.so.6
#6  0x0000000000000000 in ?? ()

Thread 1 (Thread 0x7f70529fe750 (LWP 14295)):
#0  0x00007f704d4f1ce1 in nanosleep () from /lib64/libc.so.6
#1  0x00007f704d4f1adc in sleep () from /lib64/libc.so.6
#2  0x00007f70524dfd0f in ?? () from /usr/lib64/libkdeui.so.5
#3  0x00007f70524e066a in KCrash::defaultCrashHandler(int) () from /usr/lib64/libkdeui.so.5
#4  <signal handler called>
#5  0x0000000c00000001 in ?? ()
#6  0x00007f7051757d52 in ?? () from /usr/lib64/libkmailprivate.so.4
#7  0x00007f705175dfd4 in ?? () from /usr/lib64/libkmailprivate.so.4
#8  0x00007f704f2f8454 in QMetaObject::activate(QObject*, int, int, void**) () from /usr/lib64/libQtCore.so.4
#9  0x00007f7051f11ae2 in KJob::result(KJob*) () from /usr/lib64/libkdecore.so.5
#10 0x00007f7051f11e5f in KJob::emitResult() () from /usr/lib64/libkdecore.so.5
#11 0x00007f704fb64960 in KIO::SimpleJob::slotFinished() () from /usr/lib64/libkio.so.5
#12 0x00007f704fb64a95 in KIO::ListJob::slotFinished() () from /usr/lib64/libkio.so.5
#13 0x00007f704fb6975d in KIO::ListJob::qt_metacall(QMetaObject::Call, int, void**) () from /usr/lib64/libkio.so.5
#14 0x00007f704f2f8454 in QMetaObject::activate(QObject*, int, int, void**) () from /usr/lib64/libQtCore.so.4
#15 0x00007f704fc0ea71 in KIO::SlaveInterface::dispatch(int, QByteArray const&) () from /usr/lib64/libkio.so.5
#16 0x00007f704fc0c692 in KIO::SlaveInterface::dispatch() () from /usr/lib64/libkio.so.5
#17 0x00007f704fbffb3e in KIO::Slave::gotInput() () from /usr/lib64/libkio.so.5
#18 0x00007f704fbffe48 in KIO::Slave::qt_metacall(QMetaObject::Call, int, void**) () from /usr/lib64/libkio.so.5
#19 0x00007f704f2f8454 in QMetaObject::activate(QObject*, int, int, void**) () from /usr/lib64/libQtCore.so.4
#20 0x00007f704fb373a1 in ?? () from /usr/lib64/libkio.so.5
#21 0x00007f704fb37a4a in KIO::Connection::qt_metacall(QMetaObject::Call, int, void**) () from /usr/lib64/libkio.so.5
#22 0x00007f704f2f3105 in QObject::event(QEvent*) () from /usr/lib64/libQtCore.so.4
#23 0x00007f704e0ba1bd in QApplicationPrivate::notify_helper(QObject*, QEvent*) () from /usr/lib64/libQtGui.so.4
#24 0x00007f704e0c1f8a in QApplication::notify(QObject*, QEvent*) () from /usr/lib64/libQtGui.so.4
#25 0x00007f705247dafb in KApplication::notify(QObject*, QEvent*) () from /usr/lib64/libkdeui.so.5
#26 0x00007f704f2e4091 in QCoreApplication::notifyInternal(QObject*, QEvent*) () from /usr/lib64/libQtCore.so.4
#27 0x00007f704f2e4d3a in QCoreApplicationPrivate::sendPostedEvents(QObject*, int, QThreadData*) () from /usr/lib64/libQtCore.so.4
#28 0x00007f704f30c863 in ?? () from /usr/lib64/libQtCore.so.4
#29 0x00007f70446980db in g_main_context_dispatch () from /usr/lib64/libglib-2.0.so.0
#30 0x00007f704469b8ad in ?? () from /usr/lib64/libglib-2.0.so.0
#31 0x00007f704469ba6b in g_main_context_iteration () from /usr/lib64/libglib-2.0.so.0
#32 0x00007f704f30c4ef in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib64/libQtCore.so.4
#33 0x00007f704e14a97f in ?? () from /usr/lib64/libQtGui.so.4
#34 0x00007f704f2e29a2 in QEventLoop::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib64/libQtCore.so.4
#35 0x00007f704f2e2b2d in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib64/libQtCore.so.4
#36 0x00007f704f2e4ffd in QCoreApplication::exec() () from /usr/lib64/libQtCore.so.4
#37 0x0000000000402deb in _start ()