i had the same issue on hardy heron:

bryn@dell-desktop:~$ uname -a
Linux dell-desktop 2.6.24-19-generic #1 SMP Wed Jun 18 14:43:41 UTC 2008 i686 GNU/Linux

and the backtrace is:

(no debugging symbols found)
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[Thread debugging using libthread_db enabled]
[New Thread 0xb66cb6c0 (LWP 19009)]
[New Thread 0xb58d4b90 (LWP 14321)]
(no debugging symbols found)
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(no debugging symbols found)
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[KCrash handler]
#6  0xb6fb8218 in QThread::running () from /usr/lib/libqt-mt.so.3
#7  0x081053d3 in ?? ()
#8  0x08105bb1 in ?? ()
#9  0x08074077 in ?? ()
#10 0x080aa057 in ?? ()
#11 0xb6f91704 in QObject::activate_signal () from /usr/lib/libqt-mt.so.3
#12 0xb6f921e9 in QObject::activate_signal () from /usr/lib/libqt-mt.so.3
#13 0xb78c1b19 in KAction::activated () from /usr/lib/libkdeui.so.4
#14 0xb7902452 in KAction::slotActivated () from /usr/lib/libkdeui.so.4
#15 0xb79023ec in KAction::slotButtonClicked () from /usr/lib/libkdeui.so.4
#16 0xb79eda78 in KAction::qt_invoke () from /usr/lib/libkdeui.so.4
#17 0xb6f91704 in QObject::activate_signal () from /usr/lib/libqt-mt.so.3
#18 0xb78f9584 in KToolBarButton::buttonClicked () from /usr/lib/libkdeui.so.4
#19 0xb78f9853 in KToolBarButton::mouseReleaseEvent ()
   from /usr/lib/libkdeui.so.4
#20 0xb6fc7e33 in QWidget::event () from /usr/lib/libqt-mt.so.3
#21 0xb7970061 in KToolBarButton::event () from /usr/lib/libkdeui.so.4
#22 0xb6f25c36 in QApplication::internalNotify () from /usr/lib/libqt-mt.so.3
#23 0xb6f27de5 in QApplication::notify () from /usr/lib/libqt-mt.so.3
#24 0xb76e6672 in KApplication::notify () from /usr/lib/libkdecore.so.4
#25 0xb6eb6301 in QApplication::sendSpontaneousEvent ()
   from /usr/lib/libqt-mt.so.3
#26 0xb6eb4f8d in QETWidget::translateMouseEvent ()
   from /usr/lib/libqt-mt.so.3
#27 0xb6eb312f in QApplication::x11ProcessEvent () from /usr/lib/libqt-mt.so.3
#28 0xb6eca943 in QEventLoop::processEvents () from /usr/lib/libqt-mt.so.3
#29 0xb6f40f90 in QEventLoop::enterLoop () from /usr/lib/libqt-mt.so.3
#30 0xb6f40c8e in QEventLoop::exec () from /usr/lib/libqt-mt.so.3
#31 0xb6f277df in QApplication::exec () from /usr/lib/libqt-mt.so.3
#32 0x0809104e in ?? ()
#33 0xb672e450 in __libc_start_main () from /lib/tls/i686/cmov/libc.so.6
#34 0x08068311 in ?? ()