Version:            (using KDE 4.1.1)
Installed from:    Ubuntu Packages

KMail crashs for me most of the times when I try to reply an e-mail. The same is true for forward, etc.
I deactivated the automatic spell checking in kmail, however it still seems to access the spell checker.

(gdb) backtrace
#0  0xb7f70410 in __kernel_vsyscall ()
#1  0xb65ff085 in raise () from /lib/tls/i686/cmov/libc.so.6
#2  0xb6600a01 in abort () from /lib/tls/i686/cmov/libc.so.6
#3  0xb71a1367 in qt_message_output (msgType=QtFatalMsg, buf=0xbf9e322c "ASSERT: \"dict\" in file /build/buildd/kde4libs-4.1.1+really4.1.1/kdecore/sonnet/loader.cpp, line 116") at global/qglobal.cpp:2061
#4  0xb71a1458 in qFatal (msg=0xb72e8498 "ASSERT: \"%s\" in file %s, line %d") at global/qglobal.cpp:2263
#5  0xb71a1505 in qt_assert (assertion=0xb755e041 "dict", file=0xb755de40 "/build/buildd/kde4libs-4.1.1+really4.1.1/kdecore/sonnet/loader.cpp", line=116) at global/qglobal.cpp:1831
#6  0xb74c28d2 in Sonnet::Loader::createSpeller (this=0x87ca350, language=@0x8c54588, clientName=@0xbf9e52e8) at /build/buildd/kde4libs-4.1.1+really4.1.1/kdecore/sonnet/loader.cpp:116
#7  0xb74c4dae in Sonnet::Speller::Private::recreateDict (this=0x8c54580) at /build/buildd/kde4libs-4.1.1+really4.1.1/kdecore/sonnet/speller.cpp:63
#8  0xb778181f in Sonnet::Highlighter::setCurrentLanguage (this=0x8c42778, lang=@0x8b8d97c) at /build/buildd/kde4libs-4.1.1+really4.1.1/kdeui/sonnet/highlighter.cpp:296
#9  0xb797a990 in KPIM::KMeditor::setSpellCheckLanguage () from /usr/lib/kde4/lib/libkdepim.so.4
#10 0xb797c996 in KPIM::KMeditor::createHighlighter () from /usr/lib/kde4/lib/libkdepim.so.4
#11 0xb7807881 in KTextEdit::focusInEvent (this=0x8b89cd0, event=0xbf9e5998) at /build/buildd/kde4libs-4.1.1+really4.1.1/kdeui/widgets/ktextedit.cpp:463
#12 0xb69b3b34 in QWidget::event (this=0x8b89cd0, event=0xbf9e5998) at kernel/qwidget.cpp:7119
#13 0xb6cee2a3 in QFrame::event (this=0x8b89cd0, e=0xbf9e5998) at widgets/qframe.cpp:657
#14 0xb6d82815 in QAbstractScrollArea::event (this=0x8b89cd0, e=0xbf9e5998) at widgets/qabstractscrollarea.cpp:903
#15 0xb6d6bc72 in QTextEdit::event (this=0x8b89cd0, e=0xbf9e5998) at widgets/qtextedit.cpp:1055
#16 0xb7808949 in KTextEdit::event (this=0x8b89cd0, ev=0xbf9e5998) at /build/buildd/kde4libs-4.1.1+really4.1.1/kdeui/widgets/ktextedit.cpp:241
#17 0xb695bf9c in QApplicationPrivate::notify_helper (this=0x806a078, receiver=0x8b89cd0, e=0xbf9e5998) at kernel/qapplication.cpp:3800
#18 0xb6960ce8 in QApplication::notify (this=0xbf9e6178, receiver=0x8b89cd0, e=0xbf9e5998) at kernel/qapplication.cpp:3765
#19 0xb77271c3 in KApplication::notify (this=0xbf9e6178, receiver=0x8b89cd0, event=0xbf9e5998) at /build/buildd/kde4libs-4.1.1+really4.1.1/kdeui/kernel/kapplication.cpp:311
#20 0xb72950b9 in QCoreApplication::notifyInternal (this=0xbf9e6178, receiver=0x8b89cd0, event=0xbf9e5998) at kernel/qcoreapplication.cpp:591
#21 0xb695ec0c in QApplicationPrivate::setFocusWidget (focus=0x8b89cd0, reason=Qt::ActiveWindowFocusReason) at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:215
#22 0xb69aa15e in QWidget::setFocus (this=0x8b89cd0, reason=Qt::ActiveWindowFocusReason) at kernel/qwidget.cpp:5241
#23 0xb69642d5 in QApplication::setActiveWindow (act=0x822d3a8) at kernel/qapplication.cpp:2306
#24 0xb69c6f47 in QApplication::x11ProcessEvent (this=0xbf9e6178, event=0xbf9e5e38) at kernel/qapplication_x11.cpp:3085
#25 0xb69efc2a in x11EventSourceDispatch (s=0x806ce10, callback=0, user_data=0x0) at kernel/qguieventdispatcher_glib.cpp:148
#26 0xb4d6fcc6 in g_main_context_dispatch () from /usr/lib/libglib-2.0.so.0
#27 0xb4d73083 in ?? () from /usr/lib/libglib-2.0.so.0
#28 0xb4d7363e in g_main_context_iteration () from /usr/lib/libglib-2.0.so.0
#29 0xb72c09f8 in QEventDispatcherGlib::processEvents (this=0x8069320, flags=@0xbf9e5fd8) at kernel/qeventdispatcher_glib.cpp:325
#30 0xb69efa25 in QGuiEventDispatcherGlib::processEvents (this=0x8069320, flags=@0xbf9e6008) at kernel/qguieventdispatcher_glib.cpp:204
#31 0xb729433d in QEventLoop::processEvents (this=0xbf9e6080, flags=@0xbf9e6044) at kernel/qeventloop.cpp:149
#32 0xb72944cd in QEventLoop::exec (this=0xbf9e6080, flags=@0xbf9e6088) at kernel/qeventloop.cpp:200
#33 0xb729674d in QCoreApplication::exec () at kernel/qcoreapplication.cpp:849
#34 0xb695b897 in QApplication::exec () at kernel/qapplication.cpp:3330
#35 0x0804a85f in _start ()