You can read in:
http://techbase.kde.org/Development/Tutorials/Debugging/How_to_create_useful_crash_reports 
further instructions on how to get a detailed one. 

Hum, after installing debugsource and debuginfo packages, and running kmail once. First time kmail crashed, then it works like a charm.

Please reopen this bug report if you experience the same bug again with a recent KDE and you can get a backtrace. Thanks :)

I'm having a similar crash when trying to open my Gmail inbox.
First it reports the correct number of unread emails, then I enter the inbox, it changes the number of unread mails to 1 and then crashes.

This is the backtrace:

Aplicación: Kontact (kontact), señal SIGSEGV
0x00007fb37d7b6621 in nanosleep () from /lib/libc.so.6
[Current thread is 0 (LWP 13686)]

Thread 3 (Thread 0x42742950 (LWP 13695)):
#0  0x00007fb37aca155d in pthread_cond_timedwait@@GLIBC_2.3.2 () from /lib/libpthread.so.0
#1  0x00007fb37e297327 in QWaitCondition::wait () from /usr/lib/libQtCore.so.4
#2  0x00007fb37e28d509 in ?? () from /usr/lib/libQtCore.so.4
#3  0x00007fb37e296362 in ?? () from /usr/lib/libQtCore.so.4
#4  0x00007fb37ac9d3ea in start_thread () from /lib/libpthread.so.0
#5  0x00007fb37d7f4c6d in clone () from /lib/libc.so.6
#6  0x0000000000000000 in ?? ()

Thread 2 (Thread 0x415f3950 (LWP 13696)):
#0  0x00007fb37aca155d in pthread_cond_timedwait@@GLIBC_2.3.2 () from /lib/libpthread.so.0
#1  0x00007fb37e297327 in QWaitCondition::wait () from /usr/lib/libQtCore.so.4
#2  0x00007fb37e28d509 in ?? () from /usr/lib/libQtCore.so.4
#3  0x00007fb37e296362 in ?? () from /usr/lib/libQtCore.so.4
#4  0x00007fb37ac9d3ea in start_thread () from /lib/libpthread.so.0
#5  0x00007fb37d7f4c6d in clone () from /lib/libc.so.6
#6  0x0000000000000000 in ?? ()

Thread 1 (Thread 0x7fb383b686f0 (LWP 13686)):
[KCrash Handler]
#5  0x0000000001ec84f0 in ?? ()
#6  0x00007fb36b4595df in KMFolderImap::slotListFolderResult (this=0x1a92f20, job=0x1ec5d40) at /build/buildd/kdepim-4.1.96/kmail/kmfolderimap.cpp:1355
#7  0x00007fb36b45dce4 in KMFolderImap::qt_metacall (this=0x1a92f20, _c=QMetaObject::InvokeMetaMethod, _id=<value optimized out>, _a=0x7fff8bbaabe0)
    at /build/buildd/kdepim-4.1.96/obj-x86_64-linux-gnu/kmail/kmfolderimap.moc:181
#8  0x00007fb37e393134 in QMetaObject::activate () from /usr/lib/libQtCore.so.4
#9  0x00007fb37e9c58e2 in KJob::result (this=0x1eddf50, _t1=0x1ec5d40) at /build/buildd/kde4libs-4.1.96/obj-x86_64-linux-gnu/kdecore/kjob.moc:186
#10 0x00007fb37e9c5caf in KJob::emitResult (this=0x1ec5d40) at /build/buildd/kde4libs-4.1.96/kdecore/jobs/kjob.cpp:294
#11 0x00007fb38072a600 in KIO::SimpleJob::slotFinished (this=0x1ec5d40) at /build/buildd/kde4libs-4.1.96/kio/kio/job.cpp:489
#12 0x00007fb38072a735 in KIO::ListJob::slotFinished (this=0x1ec5d40) at /build/buildd/kde4libs-4.1.96/kio/kio/job.cpp:2416
#13 0x00007fb38072cf8d in KIO::ListJob::qt_metacall (this=0x1ec5d40, _c=QMetaObject::InvokeMetaMethod, _id=<value optimized out>, _a=0x7fff8bbaaf20)
    at /build/buildd/kde4libs-4.1.96/obj-x86_64-linux-gnu/kio/jobclasses.moc:747
#14 0x00007fb37e393134 in QMetaObject::activate () from /usr/lib/libQtCore.so.4
#15 0x00007fb3807e9701 in KIO::SlaveInterface::dispatch (this=0x1c57c40, _cmd=104, rawdata=<value optimized out>) at /build/buildd/kde4libs-4.1.96/kio/kio/slaveinterface.cpp:175
#16 0x00007fb3807e61f2 in KIO::SlaveInterface::dispatch (this=0x1c57c40) at /build/buildd/kde4libs-4.1.96/kio/kio/slaveinterface.cpp:91
#17 0x00007fb3807d83e3 in KIO::Slave::gotInput (this=0x1c57c40) at /build/buildd/kde4libs-4.1.96/kio/kio/slave.cpp:322
#18 0x00007fb3807d9418 in KIO::Slave::qt_metacall (this=0x1c57c40, _c=QMetaObject::InvokeMetaMethod, _id=32277792, _a=0x7fff8bbab340)
    at /build/buildd/kde4libs-4.1.96/obj-x86_64-linux-gnu/kio/slave.moc:75
#19 0x00007fb37e393134 in QMetaObject::activate () from /usr/lib/libQtCore.so.4
#20 0x00007fb3806f5da0 in KIO::ConnectionPrivate::dequeue (this=0x1c8a790) at /build/buildd/kde4libs-4.1.96/kio/kio/connection.cpp:82
#21 0x00007fb3806f5eda in KIO::Connection::qt_metacall (this=0x1c8f2f0, _c=QMetaObject::InvokeMetaMethod, _id=32277792, _a=0x1927fa0)
    at /build/buildd/kde4libs-4.1.96/obj-x86_64-linux-gnu/kio/connection.moc:72
#22 0x00007fb37e38dda5 in QObject::event () from /usr/lib/libQtCore.so.4
#23 0x00007fb37ef15c3d in QApplicationPrivate::notify_helper () from /usr/lib/libQtGui.so.4
#24 0x00007fb37ef1d9ba in QApplication::notify () from /usr/lib/libQtGui.so.4
#25 0x00007fb38024c3cb in KApplication::notify (this=0x7fff8bbabda0, receiver=0x1c8f2f0, event=0x2207f40) at /build/buildd/kde4libs-4.1.96/kdeui/kernel/kapplication.cpp:307
#26 0x00007fb37e37ed61 in QCoreApplication::notifyInternal () from /usr/lib/libQtCore.so.4
#27 0x00007fb37e37f9fa in QCoreApplicationPrivate::sendPostedEvents () from /usr/lib/libQtCore.so.4
#28 0x00007fb37e3a74d3 in ?? () from /usr/lib/libQtCore.so.4
#29 0x00007fb3780d7d3b in g_main_context_dispatch () from /usr/lib/libglib-2.0.so.0
#30 0x00007fb3780db50d in ?? () from /usr/lib/libglib-2.0.so.0
#31 0x00007fb3780db6cb in g_main_context_iteration () from /usr/lib/libglib-2.0.so.0
#32 0x00007fb37e3a715f in QEventDispatcherGlib::processEvents () from /usr/lib/libQtCore.so.4
#33 0x00007fb37efa7a6f in ?? () from /usr/lib/libQtGui.so.4
#34 0x00007fb37e37d682 in QEventLoop::processEvents () from /usr/lib/libQtCore.so.4
#35 0x00007fb37e37d80d in QEventLoop::exec () from /usr/lib/libQtCore.so.4
#36 0x00007fb37e37fcbd in QCoreApplication::exec () from /usr/lib/libQtCore.so.4
#37 0x0000000000404a15 in main (argc=1, argv=0x7fff8bbac488) at /build/buildd/kdepim-4.1.96/kontact/src/main.cpp:218

@Javier: your crash is bug 179765 (already fixed for 4.2final). We can't be sure if it is the same as the original report.
Thanks for reporting