Version:           2.3.1 (using KDE 3.1.9)
Compiler:          gcc version 3.2.1
OS:          Linux (i686) release 2.4.20

I open the effects box, add the effect 
arts::Synth_STEREO_FIR_EQUALIZER, 
open the configuration for this effect, close the configuration box,
then remove the effect and the core is there.

Here you are the backtrace:

(no debugging symbols found)...(no debugging symbols found)...
(no debugging symbols found)...(no debugging symbols found)...
(no debugging symbols found)...(no debugging symbols found)...
(no debugging symbols found)...[New Thread 16384 (LWP 20037)]
0x411997f9 in __wait4 () at __wait4:-1
	in __wait4
#0  0x411997f9 in __wait4 () at __wait4:-1
#1  0x41222210 in __DTOR_END__ () from /lib/libc.so.6
#2  0x40f87f63 in waitpid () from /lib/libpthread.so.0
#3  0x4069a56c in KCrash::defaultCrashHandler(int) ()
   from /usr/kde31/lib/libkdecore.so.4
#4  <signal handler called>
#5  __dynamic_cast (src_ptr=0x81ed988, src_type=0x81efb18, dst_type=0x81efd18, 
    src2dst=136239728) at ../../../../libstdc++-v3/libsupc++/tinfo.cc:695
#6  0x415003c7 in Arts::KGraphLine_impl::getKGraph() ()
   from /usr/kde31/lib/libartsgui_kde.so.0
#7  0x414ffc66 in Arts::KGraphLine_impl::~KGraphLine_impl() ()
   from /usr/kde31/lib/libartsgui_kde.so.0
#8  0x41500506 in virtual thunk to Arts::KGraphLine_impl::~KGraphLine_impl() ()
   from /usr/kde31/lib/libartsgui_kde.so.0
#9  0x41e7a4da in Arts::Object_base::_destroy() ()
   from /usr/kde31/lib/libmcop.so.1
#10 0x41e7b79b in Arts::Object_skel::_release() ()
   from /usr/kde31/lib/libmcop.so.1
#11 0x41e80176 in virtual thunk to Arts::Object_skel::_release() ()
   from /usr/kde31/lib/libmcop.so.1
#12 0x41475918 in Arts::Object::Pool::Dec() ()
   from /usr/kde31/lib/libnoatun.so.1
#13 0x41e81a33 in std::_List_base<Arts::NamedStore<Arts::Object>::Element, std::allocator<Arts::NamedStore<Arts::Object>::Element> >::clear() ()
   from /usr/kde31/lib/libmcop.so.1
#14 0x41e815e2 in std::_List_base<Arts::NamedStore<Arts::Object>::Element, std::allocator<Arts::NamedStore<Arts::Object>::Element> >::~_List_base() ()
   from /usr/kde31/lib/libmcop.so.1
#15 0x41e7a6e5 in Arts::Object_base::~Object_base() ()
   from /usr/kde31/lib/libmcop.so.1
#16 0x414fd697 in Arts::KGraph_impl::~KGraph_impl() ()
   from /usr/kde31/lib/libartsgui_kde.so.0
#17 0x414fd6d6 in virtual thunk to Arts::KGraph_impl::~KGraph_impl() ()
   from /usr/kde31/lib/libartsgui_kde.so.0
#18 0x41e7a4da in Arts::Object_base::_destroy() ()
   from /usr/kde31/lib/libmcop.so.1
#19 0x41e7b79b in Arts::Object_skel::_release() ()
   from /usr/kde31/lib/libmcop.so.1
#20 0x41e80176 in virtual thunk to Arts::Object_skel::_release() ()
   from /usr/kde31/lib/libmcop.so.1
#21 0x41475918 in Arts::Object::Pool::Dec() ()
   from /usr/kde31/lib/libnoatun.so.1
#22 0x41e81a33 in std::_List_base<Arts::NamedStore<Arts::Object>::Element, std::allocator<Arts::NamedStore<Arts::Object>::Element> >::clear() ()
   from /usr/kde31/lib/libmcop.so.1
#23 0x41e815e2 in std::_List_base<Arts::NamedStore<Arts::Object>::Element, std::allocator<Arts::NamedStore<Arts::Object>::Element> >::~_List_base() ()
   from /usr/kde31/lib/libmcop.so.1
#24 0x41e7a6e5 in Arts::Object_base::~Object_base() ()
   from /usr/kde31/lib/libmcop.so.1
#25 0x414f6b4a in Arts::KVBox_impl::~KVBox_impl() ()
   from /usr/kde31/lib/libartsgui_kde.so.0
#26 0x414f6b86 in virtual thunk to Arts::KVBox_impl::~KVBox_impl() ()
   from /usr/kde31/lib/libartsgui_kde.so.0
#27 0x41e7a4da in Arts::Object_base::_destroy() ()
   from /usr/kde31/lib/libmcop.so.1
#28 0x41e7b79b in Arts::Object_skel::_release() ()
   from /usr/kde31/lib/libmcop.so.1
#29 0x41e80176 in virtual thunk to Arts::Object_skel::_release() ()
   from /usr/kde31/lib/libmcop.so.1
#30 0x414f3808 in KArtsWidget::~KArtsWidget() ()
   from /usr/kde31/lib/libartsgui_kde.so.0
#31 0x40a59068 in QWidget::~QWidget() () from /usr/lib/qt3.1/lib/libqt-mt.so.3
#32 0x414aa2d5 in EffectConfigWidget::~EffectConfigWidget() ()
   from /usr/kde31/lib/libnoatun.so.1
#33 0x414a830e in Effect::~Effect() () from /usr/kde31/lib/libnoatun.so.1
#34 0x414a9083 in Effects::remove(Effect*, bool) ()
   from /usr/kde31/lib/libnoatun.so.1
#35 0x4149dd72 in EffectView::removeEffect() ()
   from /usr/kde31/lib/libnoatun.so.1
#36 0x4149e33f in EffectView::qt_invoke(int, QUObject*) ()
   from /usr/kde31/lib/libnoatun.so.1
#37 0x40a2a769 in QObject::activate_signal(QConnectionList*, QUObject*) ()
   from /usr/lib/qt3.1/lib/libqt-mt.so.3
#38 0x40a2a60d in QObject::activate_signal(int) ()
   from /usr/lib/qt3.1/lib/libqt-mt.so.3
#39 0x40d303ee in QButton::clicked() () from /usr/lib/qt3.1/lib/libqt-mt.so.3
#40 0x40aac2f6 in QButton::mouseReleaseEvent(QMouseEvent*) ()
   from /usr/lib/qt3.1/lib/libqt-mt.so.3
#41 0x40a5e86c in QWidget::event(QEvent*) ()
   from /usr/lib/qt3.1/lib/libqt-mt.so.3
#42 0x409cca34 in QApplication::internalNotify(QObject*, QEvent*) ()
   from /usr/lib/qt3.1/lib/libqt-mt.so.3
#43 0x409cc243 in QApplication::notify(QObject*, QEvent*) ()
   from /usr/lib/qt3.1/lib/libqt-mt.so.3
#44 0x4060a1d9 in KApplication::notify(QObject*, QEvent*) ()
   from /usr/kde31/lib/libkdecore.so.4
#45 0x40972529 in QETWidget::translateMouseEvent(_XEvent const*) ()
   from /usr/lib/qt3.1/lib/libqt-mt.so.3
#46 0x409700ed in QApplication::x11ProcessEvent(_XEvent*) ()
   from /usr/lib/qt3.1/lib/libqt-mt.so.3
#47 0x4098524a in QEventLoop::processEvents(unsigned) ()
   from /usr/lib/qt3.1/lib/libqt-mt.so.3
#48 0x409e08f6 in QEventLoop::enterLoop() ()
   from /usr/lib/qt3.1/lib/libqt-mt.so.3
#49 0x409e0798 in QEventLoop::exec() () from /usr/lib/qt3.1/lib/libqt-mt.so.3
#50 0x409ccc61 in QApplication::exec() () from /usr/lib/qt3.1/lib/libqt-mt.so.3
#51 0x4076d1f2 in main () from /usr/kde31/lib/kde3/noatun.so
#52 0x0804cb2e in launch(int, char const*, char const*, char const*, int, char const*, bool, char const*, bool, char const*) ()
#53 0x0804d8e3 in handle_launcher_request(int) ()
#54 0x0804ddcc in handle_requests(int) ()
#55 0x0804ec0b in main ()
#56 0x410e2d84 in __libc_start_main () from /lib/libc.so.6