Version:           4.1.2 (KDE 4.1.2) (using 4.1.2 (KDE 4.1.2), Kubuntu packages)
Compiler:          gcc
OS:                Linux (i686) release 2.6.24-21-rt

I had this for a couple of times now but i cannot reproduce with specific steps. However the backtrace is always the same:

Anwendung: KWrite (kwrite), Signal SIGABRT
(no debugging symbols found)
(no debugging symbols found)
(no debugging symbols found)
[Thread debugging using libthread_db enabled]
[New Thread 0xb61386c0 (LWP 29155)]
[KCrash handler]
#6  0xb7ef0410 in __kernel_vsyscall ()
#7  0xb7d8f085 in raise () from /lib/tls/i686/cmov/libc.so.6
#8  0xb7d90a01 in abort () from /lib/tls/i686/cmov/libc.so.6
#9  0xb73f4367 in qt_message_output (msgType=QtFatalMsg, 
    buf=0xbff1677c "ASSERT: \"smartGroup\" in file /build/buildd/kde4libs-4.1.2/kate/smart/katesmartmanager.cpp, line 184") at global/qglobal.cpp:2061
#10 0xb73f4458 in qFatal (msg=0xb753b498 "ASSERT: \"%s\" in file %s, line %d")
    at global/qglobal.cpp:2263
#11 0xb73f4505 in qt_assert (assertion=0xb4923a98 "smartGroup", 
    file=0xb492386c "/build/buildd/kde4libs-4.1.2/kate/smart/katesmartmanager.cpp", line=184) at global/qglobal.cpp:1831
#12 0xb487f1b2 in KateSmartManager::groupForLine (this=0x81f7a18, line=85)
    at /build/buildd/kde4libs-4.1.2/kate/smart/katesmartmanager.cpp:184
#13 0xb487af27 in KateSmartCursor::setPositionInternal (this=0x84ff3d0, 
    pos=@0xbff18848, internal=true)
    at /build/buildd/kde4libs-4.1.2/kate/smart/katesmartcursor.cpp:154
#14 0xb487b3d0 in KateSmartCursor::translate (this=0x84ff3d0, edit=@0x8676720)
    at /build/buildd/kde4libs-4.1.2/kate/smart/katesmartcursor.cpp:267
#15 0xb48804b9 in KateSmartGroup::translateChanged (this=0x881a120, 
    edit=@0x8676720)
    at /build/buildd/kde4libs-4.1.2/kate/smart/katesmartmanager.cpp:324
#16 0xb48808b7 in KateSmartManager::slotTextChanged (this=0x81f7a18, 
    edit=0x8676720)
    at /build/buildd/kde4libs-4.1.2/kate/smart/katesmartmanager.cpp:246
#17 0xb4880c8a in KateSmartManager::qt_metacall (this=0x81f7a18, 
    _c=QMetaObject::InvokeMetaMethod, _id=-2, _a=0xbff18a4c)
    at /build/buildd/kde4libs-4.1.2/obj-i486-linux-gnu/kate/katesmartmanager.moc:73
#18 0xb74fcf79 in QMetaObject::activate (sender=0x81a7a30, 
    from_signal_index=4, to_signal_index=4, argv=0xbff18a4c)
    at kernel/qobject.cpp:3016
#19 0xb74fd642 in QMetaObject::activate (sender=0x81a7a30, m=0xb49349a4, 
    local_signal_index=0, argv=0xbff18a4c) at kernel/qobject.cpp:3086
#20 0xb4859863 in KateEditHistory::editDone (this=0x81a7a30, _t1=0x8676720)
    at /build/buildd/kde4libs-4.1.2/obj-i486-linux-gnu/kate/kateedit.moc:76
#21 0xb4851b30 in KateEditHistory::doEdit (this=0x81a7a30, edit=0x8676720)
    at /build/buildd/kde4libs-4.1.2/kate/document/kateedit.h:199
#22 0xb4843639 in KateDocument::editWrapLine (this=0x81a7248, line=83, col=0, 
    newLine=true, newLineAdded=0x0)
    at /build/buildd/kde4libs-4.1.2/kate/document/katedocument.cpp:1410
#23 0xb4844b04 in KateDocument::newLine (this=0x81a7248, v=0x81f8288)
    at /build/buildd/kde4libs-4.1.2/kate/document/katedocument.cpp:4096
#24 0xb48bcb91 in KateViewInternal::doReturn (this=0x81fa980)
    at /build/buildd/kde4libs-4.1.2/kate/view/kateviewinternal.cpp:742
#25 0xb48becb2 in KateViewInternal::keyPressEvent (this=0x81fa980, 
    e=0xbff190f4)
    at /build/buildd/kde4libs-4.1.2/kate/view/kateviewinternal.cpp:2202
#26 0xb48bc78f in KateViewInternal::eventFilter (this=0x81fa980, 
    obj=0x81fa980, e=0xbff190f4)
    at /build/buildd/kde4libs-4.1.2/kate/view/kateviewinternal.cpp:2133
#27 0xb74e8431 in QCoreApplicationPrivate::sendThroughObjectEventFilters (
    this=0x805b9e0, receiver=0x81fa980, event=0xbff190f4)
    at kernel/qcoreapplication.cpp:698
#28 0xb6baef73 in QApplicationPrivate::notify_helper (this=0x805b9e0, 
    receiver=0x81fa980, e=0xbff190f4) at kernel/qapplication.cpp:3796
#29 0xb6bb3f3c in QApplication::notify (this=0xbff19c40, receiver=0x81fa980, 
    e=0xbff190f4) at kernel/qapplication.cpp:3446
#30 0xb7966483 in KApplication::notify (this=0xbff19c40, receiver=0x81fa980, 
    event=0xbff190f4)
    at /build/buildd/kde4libs-4.1.2/kdeui/kernel/kapplication.cpp:311
#31 0xb74e80b9 in QCoreApplication::notifyInternal (this=0xbff19c40, 
    receiver=0x81fa980, event=0xbff190f4) at kernel/qcoreapplication.cpp:591
#32 0xb6c0aa5e in qt_sendSpontaneousEvent (receiver=0x81fa980, 
    event=0xbff190f4)
    at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:218
#33 0xb6c3f75b in QKeyMapper::sendKeyEvent (keyWidget=0x81fa980, grab=false, 
    type=QEvent::KeyPress, code=16777220, modifiers=@0xbff19260, 
    text=@0xbff19294, autorepeat=<value optimized out>, count=1, 
    nativeScanCode=36, nativeVirtualKey=65293, nativeModifiers=0)
    at kernel/qkeymapper_x11.cpp:1658
#34 0xb6c4183e in QKeyMapperPrivate::translateKeyEvent (this=0x807f780, 
    keyWidget=0x81fa980, event=0xbff197c8, grab=<value optimized out>)
    at kernel/qkeymapper_x11.cpp:1629
#35 0xb6c19d15 in QApplication::x11ProcessEvent (this=0xbff19c40, 
    event=0xbff197c8) at kernel/qapplication_x11.cpp:3059
#36 0xb6c42c2a in x11EventSourceDispatch (s=0x805e9c0, callback=0, 
    user_data=0x0) at kernel/qguieventdispatcher_glib.cpp:148
#37 0xb648fcc6 in g_main_context_dispatch () from /usr/lib/libglib-2.0.so.0
#38 0xb6493083 in ?? () from /usr/lib/libglib-2.0.so.0
#39 0xb649363e in g_main_context_iteration () from /usr/lib/libglib-2.0.so.0
#40 0xb75139f8 in QEventDispatcherGlib::processEvents (this=0x805bad8, 
    flags=@0xbff19968) at kernel/qeventdispatcher_glib.cpp:325
#41 0xb6c42a25 in QGuiEventDispatcherGlib::processEvents (this=0x805bad8, 
    flags=@0xbff19998) at kernel/qguieventdispatcher_glib.cpp:204
#42 0xb74e733d in QEventLoop::processEvents (this=0xbff19a10, 
    flags=@0xbff199d4) at kernel/qeventloop.cpp:149
#43 0xb74e74cd in QEventLoop::exec (this=0xbff19a10, flags=@0xbff19a18)
    at kernel/qeventloop.cpp:200
#44 0xb74e974d in QCoreApplication::exec () at kernel/qcoreapplication.cpp:849
#45 0xb6bae897 in QApplication::exec () at kernel/qapplication.cpp:3330
#46 0xb7ee7955 in kdemain () from /usr/lib/kde4/lib/libkdeinit4_kwrite.so
#47 0x08048582 in _start ()
#0  0xb7ef0410 in __kernel_vsyscall ()