Version:            (using KDE 4.2.98)
OS:                Linux
Installed from:    Mandriva RPMs

Try to open 4-5 folders from desktop in dolphin.While grouping the dolphin the plasma workspace shows segmentation fault.
Reproducible every time.
Attaching a ogv video also
=============================================
The trace back
=============================================

 Application: Plasma Workspace (kdeinit4), signal: Segmentation fault
[Current thread is 1 (Thread 0xb5e56a80 (LWP 20654))]

Thread 2 (Thread 0xa8ff9b70 (LWP 20657)):
#0  0xffffe424 in __kernel_vsyscall ()
#1  0xb7cecad5 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib/i686/libpthread.so.0
#2  0xb7d48280 in QWaitCondition::wait (this=0x8e7b210, mutex=0x8e7b20c, time=4294967295) at thread/qwaitcondition_unix.cpp:87
#3  0xb648bd5c in QHostInfoAgent::run (this=0x8e7b200) at kernel/qhostinfo.cpp:260
#4  0xb7d47143 in QThreadPrivate::start (arg=0x8e7b200) at thread/qthread_unix.cpp:188
#5  0xb7ce88e5 in start_thread () from /lib/i686/libpthread.so.0
#6  0xb6736bbe in clone () from /lib/i686/libc.so.6

Thread 1 (Thread 0xb5e56a80 (LWP 20654)):
[KCrash Handler]
#6  0xa90eed04 in Tasks::itemTopMargin (this=0x0) at /usr/src/debug/kdebase-workspace-4.2.98/plasma/applets/tasks/tasks.h:92
#7  0xa90edcc8 in AbstractTaskItem::basicPreferredSize (this=0x91d6350) at /usr/src/debug/kdebase-workspace-4.2.98/plasma/applets/tasks/abstracttaskitem.cpp:99
#8  0xa90e691a in TaskItemLayout::maximumRows (this=0x8ce40b8) at /usr/src/debug/kdebase-workspace-4.2.98/plasma/applets/tasks/taskitemlayout.cpp:185
#9  0xa90f0835 in TaskGroupItem::optimumCapacity (this=0x8eb53b8) at /usr/src/debug/kdebase-workspace-4.2.98/plasma/applets/tasks/taskgroupitem.cpp:1224
#10 0xa90e206a in Tasks::adjustGroupingStrategy (this=0x8d377c8) at /usr/src/debug/kdebase-workspace-4.2.98/plasma/applets/tasks/tasks.cpp:241
#11 0xa90e2c8c in Tasks::constraintsEvent (this=0x8d377c8, constraints=) at /usr/src/debug/kdebase-workspace-4.2.98/plasma/applets/tasks/tasks.cpp:165
#12 0xb5b8bef0 in Plasma::Applet::flushPendingConstraintsEvents (this=0x8d377c8) at /usr/src/debug/kdelibs-4.2.98/plasma/applet.cpp:1158
#13 0xb5b8bfe9 in Plasma::Applet::timerEvent (this=0x8d377c8, event=0xbf954980) at /usr/src/debug/kdelibs-4.2.98/plasma/applet.cpp:2102
#14 0xb7e50b2b in QObject::event (this=0x8d377c8, e=0xbf954980) at kernel/qobject.cpp:1066
#15 0xb703faf4 in QGraphicsWidget::event (this=0x8d377c8, event=0xbf954980) at graphicsview/qgraphicswidget.cpp:1340
#16 0xb69c13ac in QApplicationPrivate::notify_helper (this=0x881abf8, receiver=0x8d377c8, e=0xbf954980) at kernel/qapplication.cpp:4056
#17 0xb69c8efe in QApplication::notify (this=0x8814c00, receiver=0x8d377c8, e=0xbf954980) at kernel/qapplication.cpp:3603
#18 0xb7418e88 in KApplication::notify (this=0x8814c00, receiver=0x8d377c8, event=0xbf954980) at /usr/src/debug/kdelibs-4.2.98/kdeui/kernel/kapplication.cpp:302
#19 0xb7e4079e in QCoreApplication::notifyInternal (this=0x8814c00, receiver=0x8d377c8, event=0xbf954980) at kernel/qcoreapplication.cpp:610
#20 0xb7e6f2b9 in QTimerInfoList::activateTimers (this=0x881fb74) at ../../src/corelib/kernel/qcoreapplication.h:213
#21 0xb7e6ca8e in timerSourceDispatch (source=0x881fb40) at kernel/qeventdispatcher_glib.cpp:165
#22 0xb65abed2 in g_main_context_dispatch () from /usr/lib/libglib-2.0.so.0
#23 0xb65af888 in ?? () from /usr/lib/libglib-2.0.so.0
#24 0xb65af9ae in g_main_context_iteration () from /usr/lib/libglib-2.0.so.0
#25 0xb7e6c9d8 in QEventDispatcherGlib::processEvents (this=0x881a230, flags={i = 36}) at kernel/qeventdispatcher_glib.cpp:327
#26 0xb6a6425a in QGuiEventDispatcherGlib::processEvents (this=0x881a230, flags={i = 36}) at kernel/qguieventdispatcher_glib.cpp:202
#27 0xb7e3ed8d in QEventLoop::processEvents (this=0xbf954c04, flags=) at kernel/qeventloop.cpp:149
#28 0xb7e3f1d9 in QEventLoop::exec (this=0xbf954c04, flags={i = 0}) at kernel/qeventloop.cpp:201
#29 0xb7e416c0 in QCoreApplication::exec () at kernel/qcoreapplication.cpp:888
#30 0xb69c1214 in QApplication::exec () at kernel/qapplication.cpp:3525
#31 0xb48e74ae in kdemain (argc=1, argv=0x87d0928) at /usr/src/debug/kdebase-workspace-4.2.98/plasma/shells/desktop/main.cpp:50
#32 0x0804dbd4 in launch (argc=<value optimized out>, _name=<value optimized out>, args=<value optimized out>, cwd=0x0, envc=0, envs=0x87e5208 "", reset_env=false, tty=0x0, avoid_loops=false, 
    startup_id_str=0x8051c48 "0") at /usr/src/debug/kdelibs-4.2.98/kinit/kinit.cpp:676
#33 0x0804e345 in handle_launcher_request (sock=7, who=<value optimized out>) at /usr/src/debug/kdelibs-4.2.98/kinit/kinit.cpp:1168
#34 0x0804f0b4 in handle_requests (waitForPid=<value optimized out>) at /usr/src/debug/kdelibs-4.2.98/kinit/kinit.cpp:1361
#35 0x0804f945 in main (argc=2, argv=0xbf955324, envp=0xbf955330) at /usr/src/debug/kdelibs-4.2.98/kinit/kinit.cpp:1788
==========================================
thanks
dhiraj