Application that crashed: kontact
Version of the application: 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 x86_64
Distribution: Ubuntu 9.04

What I was doing when the application crashed:
After booting up my system, logging-in in KDE. The following message appears:

"Kontact already seems to be running on another display on this machine. Running Kontact more than once can cause the loss of mail. You should not start Kontact unless you are sure that it is not already running."

Then I have two options either "Exit" ot "start", if I press start, The Kmail icon in the systemtray appears two times. If I right click on one of them, and then "Quit", Kontact crashes.

 -- Backtrace:
Application: Kontact (kontact), signal: Segmentation fault
[Current thread is 0 (LWP 5336)]

Thread 3 (Thread 0x7f823cb52950 (LWP 5371)):
#0  pthread_cond_timedwait@@GLIBC_2.3.2 () at ../nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_timedwait.S:217
#1  0x00007f8259998cf7 in QWaitCondition::wait (this=0x45528d8, mutex=0x45528d0, time=30000) at thread/qwaitcondition_unix.cpp:85
#2  0x00007f825998e929 in QThreadPoolThread::run (this=0x3f02c40) at concurrent/qthreadpool.cpp:140
#3  0x00007f8259997d35 in QThreadPrivate::start (arg=0x3f02c40) at thread/qthread_unix.cpp:188
#4  0x00007f82562713ba in start_thread (arg=<value optimized out>) at pthread_create.c:297
#5  0x00007f8258f02fcd in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:112
#6  0x0000000000000000 in ?? ()

Thread 2 (Thread 0x7f823bd23950 (LWP 5372)):
#0  pthread_cond_timedwait@@GLIBC_2.3.2 () at ../nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_timedwait.S:217
#1  0x00007f8259998cf7 in QWaitCondition::wait (this=0x45528d8, mutex=0x45528d0, time=30000) at thread/qwaitcondition_unix.cpp:85
#2  0x00007f825998e929 in QThreadPoolThread::run (this=0x40244e0) at concurrent/qthreadpool.cpp:140
#3  0x00007f8259997d35 in QThreadPrivate::start (arg=0x40244e0) at thread/qthread_unix.cpp:188
#4  0x00007f82562713ba in start_thread (arg=<value optimized out>) at pthread_create.c:297
#5  0x00007f8258f02fcd in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:112
#6  0x0000000000000000 in ?? ()

Thread 1 (Thread 0x7f825f4f2750 (LWP 5336)):
[KCrash Handler]
#5  KMSystemTray::prettyName (this=<value optimized out>, fldr=0x0) at /build/buildd/kdepim-4.3.0/kmail/kmsystemtray.cpp:352
#6  0x00007f8246faeced in KMSystemTray::slotContextMenuAboutToShow (this=0x42c5080) at /build/buildd/kdepim-4.3.0/kmail/kmsystemtray.cpp:330
#7  0x00007f8246faf1d0 in KMSystemTray::qt_metacall (this=0x42c5080, _c=QMetaObject::InvokeMetaMethod, _id=<value optimized out>, _a=0x7fff6753ae00)
    at /build/buildd/kdepim-4.3.0/obj-x86_64-linux-gnu/kmail/kmsystemtray.moc:80
#8  0x00007f8259a96ea2 in QMetaObject::activate (sender=0x42c52a0, from_signal_index=<value optimized out>, to_signal_index=27, argv=0x31) at kernel/qobject.cpp:3113
#9  0x00007f825aa05aa8 in QMenu::popup (this=0x42c52a0, p=@0x7fff6753af80, atAction=0x0) at widgets/qmenu.cpp:1790
#10 0x00007f825ac1cccc in QSystemTrayIconSys::mousePressEvent (this=0x42cbd60, ev=0x7fff6753b6e0) at util/qsystemtrayicon_x11.cpp:290
#11 0x00007f825a651296 in QWidget::event (this=0x42cbd60, event=0x7fff6753b6e0) at kernel/qwidget.cpp:7545
#12 0x00007f825a5fff4d in QApplicationPrivate::notify_helper (this=0x23dda80, receiver=0x42cbd60, e=0x7fff6753b6e0) at kernel/qapplication.cpp:4056
#13 0x00007f825a6088ea in QApplication::notify (this=<value optimized out>, receiver=0x42cbd60, e=0x7fff6753b6e0) at kernel/qapplication.cpp:3758
#14 0x00007f825ba0471b in KApplication::notify (this=0x7fff6753d630, receiver=0x42cbd60, event=0x7fff6753b6e0) at /build/buildd/kde4libs-4.3.0/kdeui/kernel/kapplication.cpp:302
#15 0x00007f8259a816ac in QCoreApplication::notifyInternal (this=0x7fff6753d630, receiver=0x42cbd60, event=0x7fff6753b6e0) at kernel/qcoreapplication.cpp:610
#16 0x00007f825a607b38 in QApplicationPrivate::sendMouseEvent (receiver=0x42cbd60, event=0x7fff6753b6e0, alienWidget=0x0, nativeWidget=0x42cbd60, buttonDown=<value optimized out>, 
    lastMouseReceiver=@0x7f825b037010) at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:216
#17 0x00007f825a671b19 in QETWidget::translateMouseEvent (this=0x42cbd60, event=<value optimized out>) at kernel/qapplication_x11.cpp:4409
#18 0x00007f825a670b53 in QApplication::x11ProcessEvent (this=0x7fff6753d630, event=0x7fff6753d260) at kernel/qapplication_x11.cpp:3550
#19 0x00007f825a699454 in x11EventSourceDispatch (s=0x23dae20, callback=0, user_data=0x0) at kernel/qguieventdispatcher_glib.cpp:146
#20 0x00007f82531d220a in g_main_context_dispatch () from /usr/lib/libglib-2.0.so.0
#21 0x00007f82531d58e0 in ?? () from /usr/lib/libglib-2.0.so.0
#22 0x00007f82531d5a7c in g_main_context_iteration () from /usr/lib/libglib-2.0.so.0
#23 0x00007f8259aaaa8f in QEventDispatcherGlib::processEvents (this=0x23ab0a0, flags=<value optimized out>) at kernel/qeventdispatcher_glib.cpp:327
#24 0x00007f825a698bdf in QGuiEventDispatcherGlib::processEvents (this=0x7fff6753acf0, flags=<value optimized out>) at kernel/qguieventdispatcher_glib.cpp:202
#25 0x00007f8259a7ff42 in QEventLoop::processEvents (this=<value optimized out>, flags={i = 1733547344}) at kernel/qeventloop.cpp:149
#26 0x00007f8259a80314 in QEventLoop::exec (this=0x7fff6753d590, flags={i = 1733547424}) at kernel/qeventloop.cpp:201
#27 0x00007f8259a825e4 in QCoreApplication::exec () at kernel/qcoreapplication.cpp:888
#28 0x0000000000404945 in main (argc=3, argv=0x7fff6753dd18) at /build/buildd/kdepim-4.3.0/kontact/src/main.cpp:218

Reported using DrKonqi