Application that crashed: plasma-desktop
Version of the application: 0.3
KDE Version: 4.3.00 (KDE 4.3.0)
Qt Version: 4.5.2
Operating System: Linux 2.6.30-1-686 i686
Distribution: Debian GNU/Linux unstable (sid)

What I was doing when the application crashed:
Launching Mozilla Thunderbird 3 b3 as downloaded from mozilla from a .desktop icon on the taskbar causes a "Sorry - Plasma Workspace: Error launching /home/loudergood/.local/share/applications/Thunderbird.desktop.
Either KLauncher is not running anymore, or it failed to start the application." dialog box to appear. Thunderbird functions as expected.

 -- Backtrace:
Application: Plasma Workspace (kdeinit4), signal: Segmentation fault
[Current thread is 1 (Thread 0xb60b0920 (LWP 3087))]

Thread 3 (Thread 0xa5913b90 (LWP 3088)):
#0  0xb68a9fec in clock_gettime () from /lib/i686/cmov/librt.so.1
#1  0xb7fdd51b in QTimerInfoList::getTime (this=0x9c83834, t=...) at kernel/qeventdispatcher_unix.cpp:339
#2  0xb7fdd6e1 in QTimerInfoList::updateCurrentTime (this=0x9c83834) at kernel/qeventdispatcher_unix.cpp:297
#3  0xb7fdf41c in QTimerInfoList::timerWait (this=0x9c83834, tm=...) at kernel/qeventdispatcher_unix.cpp:420
#4  0xb7fdba3a in timerSourcePrepare (source=0xb68adff4, timeout=0xa5911c28) at kernel/qeventdispatcher_glib.cpp:141
#5  0xb682ce30 in g_main_context_prepare () from /usr/lib/libglib-2.0.so.0
#6  0xb682d1f4 in ?? () from /usr/lib/libglib-2.0.so.0
#7  0xb682d698 in g_main_context_iteration () from /usr/lib/libglib-2.0.so.0
#8  0xb7fdb877 in QEventDispatcherGlib::processEvents (this=0x9c37950, flags=...) at kernel/qeventdispatcher_glib.cpp:329
#9  0xb7faf01a in QEventLoop::processEvents (this=0xa5911d94, flags=...) at kernel/qeventloop.cpp:149
#10 0xb7faf462 in QEventLoop::exec (this=0xa5911d94, flags=...) at kernel/qeventloop.cpp:201
#11 0xb79c14eb in KIO::NetAccess::enter_loop (this=0xa5911e00) at ../../kio/kio/netaccess.cpp:502
#12 0xb79c1baf in KIO::NetAccess::synchronousRunInternal (this=0xa5911e00, job=0x9623fe0, window=0x0, data=0xa5911e84, finalURL=0x0, metaData=0x0) at ../../kio/kio/netaccess.cpp:487
#13 0xb79c2231 in KIO::NetAccess::synchronousRun (job=0x9623fe0, window=0x0, data=0xa5911e84, finalURL=0x0, metaData=0x0) at ../../kio/kio/netaccess.cpp:277
#14 0xa95a1b3a in ?? () from /usr/lib/kde4/plasma_applet_cwp.so
#15 0xa95add92 in ?? () from /usr/lib/kde4/plasma_applet_cwp.so
#16 0xa95aec10 in ?? () from /usr/lib/kde4/plasma_applet_cwp.so
#17 0xb7ebf582 in QThreadPrivate::start (arg=0x9623fe0) at thread/qthread_unix.cpp:188
#18 0xb67db4b5 in start_thread () from /lib/i686/cmov/libpthread.so.0
#19 0xb69aaa5e in clone () from /lib/i686/cmov/libc.so.6

Thread 2 (Thread 0xa45b3b90 (LWP 3092)):
#0  0xb80be424 in __kernel_vsyscall ()
#1  0xb67def65 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib/i686/cmov/libpthread.so.0
#2  0xb69b985d in pthread_cond_wait () from /lib/i686/cmov/libc.so.6
#3  0xb7ec0562 in QWaitConditionPrivate::wait (this=0x9cbdf30, mutex=0x9cbdf2c, time=4294967295) at thread/qwaitcondition_unix.cpp:87
#4  QWaitCondition::wait (this=0x9cbdf30, mutex=0x9cbdf2c, time=4294967295) at thread/qwaitcondition_unix.cpp:159
#5  0xb66e567a in QHostInfoAgent::run (this=0x9cbdf20) at kernel/qhostinfo.cpp:260
#6  0xb7ebf582 in QThreadPrivate::start (arg=0x9cbdf20) at thread/qthread_unix.cpp:188
#7  0xb67db4b5 in start_thread () from /lib/i686/cmov/libpthread.so.0
#8  0xb69aaa5e in clone () from /lib/i686/cmov/libc.so.6

Thread 1 (Thread 0xb60b0920 (LWP 3087)):
[KCrash Handler]
#6  Tasks::itemTopMargin (this=0x9006c78) at ../../../../plasma/applets/tasks/tasks.h:92
#7  AbstractTaskItem::basicPreferredSize (this=0x9006c78) at ../../../../plasma/applets/tasks/abstracttaskitem.cpp:100
#8  0xa93f6471 in TaskItemLayout::preferredColumns (this=0x9089230) at ../../../../plasma/applets/tasks/taskitemlayout.cpp:206
#9  0xa93f6e5d in TaskItemLayout::gridLayoutSize (this=0x9089230) at ../../../../plasma/applets/tasks/taskitemlayout.cpp:222
#10 0xa93f6f1b in TaskItemLayout::layoutItems (this=0x9089230) at ../../../../plasma/applets/tasks/taskitemlayout.cpp:245
#11 0xa93f78d4 in TaskItemLayout::remove (this=0x9089230, item=0xa1226f8) at ../../../../plasma/applets/tasks/taskitemlayout.cpp:136
#12 0xa93f798c in TaskItemLayout::removeTaskItem (this=0x9089230, item=0xa1226f8) at ../../../../plasma/applets/tasks/taskitemlayout.cpp:93
#13 0xa94039c6 in TaskGroupItem::itemRemoved (this=0x9d2f1e8, groupableItem=0x9fa6088) at ../../../../plasma/applets/tasks/taskgroupitem.cpp:521
#14 0xa9404edc in TaskGroupItem::qt_metacall (this=0x9d2f1e8, _c=QMetaObject::InvokeMetaMethod, _id=15, _a=0xbfda131c) at ./taskgroupitem.moc:114
#15 0xb7fc5b33 in QMetaObject::activate (sender=0x9cee770, from_signal_index=22, to_signal_index=22, argv=0xbfda131c) at kernel/qobject.cpp:3112
#16 0xb7fc6782 in QMetaObject::activate (sender=0x9cee770, m=0xa94b0154, local_signal_index=1, argv=0xbfda131c) at kernel/qobject.cpp:3186
#17 0xa94a1bd3 in TaskManager::TaskGroup::itemRemoved (this=0x9cee770, _t1=0x9fa6088) at ./taskgroup.moc:146
#18 0xa94a25eb in TaskManager::TaskGroup::remove (this=0x9cee770, item=0x9fa6088) at ../../../libs/taskmanager/taskgroup.cpp:182
#19 0xa948979d in TaskManager::GroupManagerPrivate::removeTask (this=0x9d01910, task=...) at ../../../libs/taskmanager/groupmanager.cpp:311
#20 0xa948b0da in TaskManager::GroupManager::qt_metacall (this=0x9d0d188, _c=QMetaObject::InvokeMetaMethod, _id=11, _a=0xbfda14bc) at ./groupmanager.moc:105
#21 0xb7fc5b33 in QMetaObject::activate (sender=0x9cee110, from_signal_index=5, to_signal_index=5, argv=0xbfda14bc) at kernel/qobject.cpp:3112
#22 0xb7fc6782 in QMetaObject::activate (sender=0x9cee110, m=0xa94b031c, local_signal_index=1, argv=0xbfda14bc) at kernel/qobject.cpp:3186
#23 0xa94a55f3 in TaskManager::TaskManager::taskRemoved (this=0x9cee110, _t1=...) at ./taskmanager.moc:162
#24 0xa94a6e41 in TaskManager::TaskManager::windowRemoved (this=0x9cee110, w=23282124) at ../../../libs/taskmanager/taskmanager.cpp:279
#25 0xa94a8d44 in TaskManager::TaskManager::qt_metacall (this=0x9cee110, _c=QMetaObject::InvokeMetaMethod, _id=7, _a=0xbfda162c) at ./taskmanager.moc:110
#26 0xb7fc5b33 in QMetaObject::activate (sender=0x8fd2258, from_signal_index=6, to_signal_index=6, argv=0xbfda162c) at kernel/qobject.cpp:3112
#27 0xb7fc6782 in QMetaObject::activate (sender=0x8fd2258, m=0xb785364c, local_signal_index=2, argv=0xbfda162c) at kernel/qobject.cpp:3186
#28 0xb77ed083 in KWindowSystem::windowRemoved (this=0x8fd2258, _t1=23282124) at ./kwindowsystem.moc:127
#29 0xb77ef856 in KWindowSystemPrivate::removeClient (this=0x8fb8248, w=23282124) at ../../kdeui/windowmanagement/kwindowsystem_x11.cpp:249
#30 0xb77fe40d in NETRootInfo::update (this=0x8fb825c, dirty_props=0xbfda17f8) at ../../kdeui/windowmanagement/netwm.cpp:2183
#31 0xb77ff03e in NETRootInfo::event (this=0x8fb825c, event=0xbfda2edc, properties=0xbfda1878, properties_size=5) at ../../kdeui/windowmanagement/netwm.cpp:2058
#32 0xb77efadd in KWindowSystemPrivate::x11Event (this=0x8fb8248, ev=0xbfda2e7c) at ../../kdeui/windowmanagement/kwindowsystem_x11.cpp:136
#33 0xb76a3399 in KAppX11HackWidget::publicx11Event (this=0x8e243f0, _event=0xbfda2e7c) at ../../kdeui/kernel/kapplication.cpp:900
#34 KApplication::x11EventFilter (this=0x8e243f0, _event=0xbfda2e7c) at ../../kdeui/kernel/kapplication.cpp:950
#35 0xb4c9d63c in PlasmaApp::x11EventFilter (this=0x8e243f0, event=0xbfda2e7c) at ../../../../plasma/shells/desktop/plasmaapp.cpp:490
#36 0xb6cbdade in qt_x11EventFilter (ev=0xbfda2e7c) at kernel/qapplication_x11.cpp:375
#37 0xb6ccfb7b in QApplication::x11ProcessEvent (this=0x8e243f0, event=0xbfda2e7c) at kernel/qapplication_x11.cpp:3271
#38 0xb6cfb892 in x11EventSourceDispatch (s=0x8e4e168, callback=0, user_data=0x0) at kernel/qguieventdispatcher_glib.cpp:146
#39 0xb6829d88 in g_main_context_dispatch () from /usr/lib/libglib-2.0.so.0
#40 0xb682d513 in ?? () from /usr/lib/libglib-2.0.so.0
#41 0xb682d698 in g_main_context_iteration () from /usr/lib/libglib-2.0.so.0
#42 0xb7fdb858 in QEventDispatcherGlib::processEvents (this=0x8e4b080, flags=...) at kernel/qeventdispatcher_glib.cpp:327
#43 0xb6cfafd5 in QGuiEventDispatcherGlib::processEvents (this=0x8e4b080, flags=...) at kernel/qguieventdispatcher_glib.cpp:202
#44 0xb7faf01a in QEventLoop::processEvents (this=0xbfda30e0, flags=...) at kernel/qeventloop.cpp:149
#45 0xb7faf462 in QEventLoop::exec (this=0xbfda30e0, flags=...) at kernel/qeventloop.cpp:201
#46 0xb7fb18b9 in QCoreApplication::exec () at kernel/qcoreapplication.cpp:888
#47 0xb6c5b697 in QApplication::exec () at kernel/qapplication.cpp:3525
#48 0xb4c87ee0 in kdemain (argc=1, argv=0x8dd6210) at ../../../../plasma/shells/desktop/main.cpp:50
#49 0x0804e291 in launch (argc=1, _name=0x8e0e5d4 "/usr/bin/plasma-desktop", args=0x8e0e5ec "", cwd=0x0, envc=0, envs=0x8e0e5f0 "", reset_env=false, tty=0x0, avoid_loops=false, 
    startup_id_str=0x805109f "0") at ../../kinit/kinit.cpp:676
#50 0x0804ea15 in handle_launcher_request (sock=7, who=<value optimized out>) at ../../kinit/kinit.cpp:1168
#51 0x0804ef3f in handle_requests (waitForPid=0) at ../../kinit/kinit.cpp:1361
#52 0x0804f6c9 in main (argc=2, argv=0xbfda3964, envp=0xbfda3970) at ../../kinit/kinit.cpp:1788

Reported using DrKonqi