Application that crashed: plasma-desktop
Version of the application: 0.3
KDE Version: 4.2.95 (KDE 4.2.95 (KDE 4.3 RC1))
Qt Version: 4.5.0
Operating System: Linux 2.6.28-13-generic i686
Distribution: Ubuntu 9.04

What I was doing when the application crashed:
the desktop and all the plasma realted things sudenly disapeared (crashed)

 -- Backtrace:
Application: Plasma Workspace (kdeinit4), signal: Segmentation fault
[Current thread is 0 (LWP 3386)]

Thread 2 (Thread 0xa91efb90 (LWP 3389)):
#0  0xb7f47430 in __kernel_vsyscall ()
#1  0xb64100e5 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib/tls/i686/cmov/libpthread.so.0
#2  0xb65f02ed in __pthread_cond_wait (cond=0xa3293d8, mutex=0xa3293c0) at forward.c:139
#3  0xb7d439b2 in QWaitCondition::wait () from /usr/lib/libQtCore.so.4
#4  0xb767f152 in ?? () from /usr/lib/libQtNetwork.so.4
#5  0xb7d4296e in ?? () from /usr/lib/libQtCore.so.4
#6  0xb640c4ff in start_thread (arg=0xa91efb90) at pthread_create.c:297
#7  0xb65e149e in clone () at ../sysdeps/unix/sysv/linux/i386/clone.S:130

Thread 1 (Thread 0xb5f1aa10 (LWP 3386)):
[KCrash Handler]
#6  0xa949232a in TaskManager::GroupManager::manualSortingRequest () from /usr/lib/libtaskmanager.so.4
#7  0xa949031b in TaskManager::AbstractGroupingStrategy::closeGroup () from /usr/lib/libtaskmanager.so.4
#8  0xa9497f27 in ?? () from /usr/lib/libtaskmanager.so.4
#9  0xa9498e5b in ?? () from /usr/lib/libtaskmanager.so.4
#10 0xb7e4cca8 in QMetaObject::activate () from /usr/lib/libQtCore.so.4
#11 0xb7e4d932 in QMetaObject::activate () from /usr/lib/libQtCore.so.4
#12 0xa94abd83 in TaskManager::TaskGroup::itemRemoved () from /usr/lib/libtaskmanager.so.4
#13 0xa94ac7ab in TaskManager::TaskGroup::remove () from /usr/lib/libtaskmanager.so.4
#14 0xa9492ba5 in ?? () from /usr/lib/libtaskmanager.so.4
#15 0xa949546a in TaskManager::GroupManager::qt_metacall () from /usr/lib/libtaskmanager.so.4
#16 0xb7e4cca8 in QMetaObject::activate () from /usr/lib/libQtCore.so.4
#17 0xb7e4d932 in QMetaObject::activate () from /usr/lib/libQtCore.so.4
#18 0xa94af823 in TaskManager::TaskManager::taskRemoved () from /usr/lib/libtaskmanager.so.4
#19 0xa94b10cf in TaskManager::TaskManager::windowRemoved () from /usr/lib/libtaskmanager.so.4
#20 0xa94b2fec in TaskManager::TaskManager::qt_metacall () from /usr/lib/libtaskmanager.so.4
#21 0xb7e4cca8 in QMetaObject::activate () from /usr/lib/libQtCore.so.4
#22 0xb7e4d932 in QMetaObject::activate () from /usr/lib/libQtCore.so.4
#23 0xb754d853 in KWindowSystem::windowRemoved () from /usr/lib/libkdeui.so.5
#24 0xb75500d6 in ?? () from /usr/lib/libkdeui.so.5
#25 0xb755f7c2 in NETRootInfo::update () from /usr/lib/libkdeui.so.5
#26 0xb755fb3f in NETRootInfo::event () from /usr/lib/libkdeui.so.5
#27 0xb755036d in ?? () from /usr/lib/libkdeui.so.5
#28 0xb74006f9 in KApplication::x11EventFilter () from /usr/lib/libkdeui.so.5
#29 0xb4a88e37 in ?? () from /usr/lib/libkdeinit4_plasma-desktop.so
#30 0xb6929f3e in ?? () from /usr/lib/libQtGui.so.4
#31 0xb693c6a8 in QApplication::x11ProcessEvent () from /usr/lib/libQtGui.so.4
#32 0xb6968c6a in ?? () from /usr/lib/libQtGui.so.4
#33 0xb6459b88 in g_main_context_dispatch () from /usr/lib/libglib-2.0.so.0
#34 0xb645d0eb in ?? () from /usr/lib/libglib-2.0.so.0
#35 0xb645d268 in g_main_context_iteration () from /usr/lib/libglib-2.0.so.0
#36 0xb7e62438 in QEventDispatcherGlib::processEvents () from /usr/lib/libQtCore.so.4
#37 0xb6968365 in ?? () from /usr/lib/libQtGui.so.4
#38 0xb7e3506a in QEventLoop::processEvents () from /usr/lib/libQtCore.so.4
#39 0xb7e354aa in QEventLoop::exec () from /usr/lib/libQtCore.so.4
#40 0xb7e37959 in QCoreApplication::exec () from /usr/lib/libQtCore.so.4
#41 0xb68c6d17 in QApplication::exec () from /usr/lib/libQtGui.so.4
#42 0xb4a73510 in kdemain () from /usr/lib/libkdeinit4_plasma-desktop.so
#43 0x0804e1c0 in _start ()

Reported using DrKonqi