Version:           1.9.50 (using 4.00.80 (KDE 4.0.80 >= 20080104), Gentoo)
Compiler:          i686-pc-linux-gnu-gcc
OS:                Linux (i686) release 2.6.22-gentoo-r9

When I try to move a mail from an IMAP account to a local folder (drag and drop) KMail crashes with the following backtrace:

Using host libthread_db library "/lib/libthread_db.so.1".
[Thread debugging using libthread_db enabled]
[New Thread 0xb534f6d0 (LWP 7003)]
[KCrash handler]
#6  0xffffe410 in __kernel_vsyscall ()
#7  0xb56f71f1 in *__GI_raise (sig=6)
    at ../nptl/sysdeps/unix/sysv/linux/raise.c:64
#8  0xb56f89b8 in *__GI_abort () at abort.c:88
#9  0xb7dae265 in qt_message_output (msgType=QtFatalMsg, 
    buf=0xbf94e5cc "ASSERT: \"!isEmpty()\" in file /usr/include/qt4/QtCore/qlist.h, line 242") at global/qglobal.cpp:2160
#10 0xb7dae32a in qFatal (msg=0xb7eb587c "ASSERT: \"%s\" in file %s, line %d")
    at global/qglobal.cpp:2392
#11 0xb7dae555 in qt_assert (assertion=0xb37008b6 "!isEmpty()", 
    file=0xb3700088 "/usr/include/qt4/QtCore/qlist.h", line=242)
    at global/qglobal.cpp:1917
#12 0xb34b5aea in QList<int>::first (this=0xbf950654)
    at /usr/include/qt4/QtCore/qlist.h:242
#13 0xb352e4db in KMFolderImap::addMsg (this=0x82fa658, aMsg=0x8626350, 
    aIndex_ret=0xbf95069c)
    at /var/tmp/portage/kde-base/kdepim-9999.4/work/kdepim-9999.4/kmail/kmfolderimap.cpp:413
#14 0xb34b0d7b in FolderStorage::addMessages (this=0x82fa658, 
    msgList=@0xbf950728, index_ret=@0xbf9506e8)
    at /var/tmp/portage/kde-base/kdepim-9999.4/work/kdepim-9999.4/kmail/folderstorage.cpp:1162
#15 0xb34b2a25 in FolderStorage::moveMsg (this=0x82fa658, 
    msglist=@0xbf950728, aIndex_ret=0xbf9507d8)
    at /var/tmp/portage/kde-base/kdepim-9999.4/work/kdepim-9999.4/kmail/folderstorage.cpp:626
#16 0xb3496000 in KMFolder::moveMsg (this=0x82fa5b8, q=@0xbf9507fc, 
    index_return=0xbf9507d8)
    at /var/tmp/portage/kde-base/kdepim-9999.4/work/kdepim-9999.4/kmail/kmfolder.cpp:437
#17 0xb35d680b in KMMoveCommand::execute (this=0x84e29a8)
    at /var/tmp/portage/kde-base/kdepim-9999.4/work/kdepim-9999.4/kmail/kmcommands.cpp:2133
#18 0xb35e1f7d in KMCommand::slotPostTransfer (this=0x84e29a8, 
    result=KMCommand::OK)
    at /var/tmp/portage/kde-base/kdepim-9999.4/work/kdepim-9999.4/kmail/kmcommands.cpp:270
#19 0xb35e23f6 in KMCommand::qt_metacall (this=0x84e29a8, 
    _c=QMetaObject::InvokeMetaMethod, _id=9, _a=0xbf950d9c)
    at /var/tmp/portage/kde-base/kdepim-9999.4/work/kdepim_build/kmail/kmcommands.moc:85
#20 0xb35e289a in KMMoveCommand::qt_metacall (this=0x84e29a8, 
    _c=QMetaObject::InvokeMetaMethod, _id=9, _a=0xbf950d9c)
    at /var/tmp/portage/kde-base/kdepim-9999.4/work/kdepim_build/kmail/kmcommands.moc:1661
#21 0xb7e941f4 in QMetaObject::activate (sender=0x84e29a8, 
    from_signal_index=4, to_signal_index=4, argv=<value optimized out>)
    at kernel/qobject.cpp:3081
#22 0xb7e94d94 in QMetaObject::activate (sender=0x84e29a8, m=0xb3778214, 
    local_signal_index=0, argv=0xbf950d9c) at kernel/qobject.cpp:3140
#23 0xb35ce581 in KMCommand::messagesTransfered (this=0x84e29a8, 
    _t1=KMCommand::OK)
    at /var/tmp/portage/kde-base/kdepim-9999.4/work/kdepim_build/kmail/kmcommands.moc:99
#24 0xb35e1e9b in KMCommand::transferSelectedMsgs (this=0x84e29a8)
    at /var/tmp/portage/kde-base/kdepim-9999.4/work/kdepim-9999.4/kmail/kmcommands.cpp:364
#25 0xb35e2266 in KMCommand::slotStart (this=0x84e29a8)
    at /var/tmp/portage/kde-base/kdepim-9999.4/work/kdepim-9999.4/kmail/kmcommands.cpp:262
#26 0xb35e23dc in KMCommand::qt_metacall (this=0x84e29a8, 
    _c=QMetaObject::InvokeMetaMethod, _id=8, _a=0xbf9513a4)
    at /var/tmp/portage/kde-base/kdepim-9999.4/work/kdepim_build/kmail/kmcommands.moc:84
#27 0xb35e289a in KMMoveCommand::qt_metacall (this=0x84e29a8, 
    _c=QMetaObject::InvokeMetaMethod, _id=8, _a=0xbf9513a4)
    at /var/tmp/portage/kde-base/kdepim-9999.4/work/kdepim_build/kmail/kmcommands.moc:1661
#28 0xb7e941f4 in QMetaObject::activate (sender=0x850e650, 
    from_signal_index=4, to_signal_index=4, argv=<value optimized out>)
    at kernel/qobject.cpp:3081
#29 0xb7e94d94 in QMetaObject::activate (sender=0x850e650, m=0xb7f32c64, 
    local_signal_index=0, argv=0x0) at kernel/qobject.cpp:3140
#30 0xb7e9d3c3 in QSingleShotTimer::timeout (this=0x850e650)
    at .moc/debug-shared/qtimer.moc:73
#31 0xb7e9d40c in QSingleShotTimer::timerEvent (this=0x850e650)
    at kernel/qtimer.cpp:296
#32 0xb7e92269 in QObject::event (this=0x850e650, e=0x1b5b)
    at kernel/qobject.cpp:1086
#33 0xb6d54e8a in QApplicationPrivate::notify_helper (this=0x8060068, 
    receiver=0x850e650, e=0xbf9518d8) at kernel/qapplication.cpp:3556
#34 0xb6d5677a in QApplication::notify (this=0xbf951b60, receiver=0x850e650, 
    e=0xbf9518d8) at kernel/qapplication.cpp:3115
#35 0xb7a06fb3 in KApplication::notify (this=0xbf951b60, receiver=0x850e650, 
    event=0xbf9518d8)
    at /var/tmp/portage/kde-base/kdelibs-9999.4/work/kdelibs-9999.4/kdeui/kernel/kapplication.cpp:314
#36 0xb7e80d7b in QCoreApplication::notifyInternal (this=0xbf951b60, 
    receiver=0x850e650, event=0xbf9518d8) at kernel/qcoreapplication.cpp:530
#37 0xb7ea9efb in QTimerInfoList::activateTimers (this=0x80607e4)
    at kernel/qcoreapplication.h:200
#38 0xb7ea9fd1 in QEventDispatcherUNIX::activateTimers (this=0x805f170)
    at kernel/qeventdispatcher_unix.cpp:828
#39 0xb7eaa9ab in QEventDispatcherUNIX::processEvents (this=0x805f170, 
    flags=@0xbf951a58) at kernel/qeventdispatcher_unix.cpp:890
#40 0xb6ddecce in QEventDispatcherX11::processEvents (this=0x805f170, 
    flags=@0xbf951a84) at kernel/qeventdispatcher_x11.cpp:145
#41 0xb7e80191 in QEventLoop::processEvents (this=0xbf951af0, 
    flags=@0xbf951ab8) at kernel/qeventloop.cpp:140
#42 0xb7e8029a in QEventLoop::exec (this=0xbf951af0, flags=@0xbf951af8)
    at kernel/qeventloop.cpp:186
#43 0xb7e82626 in QCoreApplication::exec () at kernel/qcoreapplication.cpp:759
#44 0xb6d54487 in QApplication::exec () at kernel/qapplication.cpp:3053
#45 0x0804b3e5 in main (argc=1, argv=0xbf951cf4)
    at /var/tmp/portage/kde-base/kdepim-9999.4/work/kdepim-9999.4/kontact/src/main.cpp:162
#46 0xb56e3fdc in __libc_start_main (main=0x804ab50 <main>, argc=1, 
    ubp_av=0xbf951cf4, init=0x804c170 <__libc_csu_init>, 
    fini=0x804c160 <__libc_csu_fini>, rtld_fini=0xb7f44100 <_dl_fini>, 
    stack_end=0xbf951cec) at libc-start.c:229
#47 0x0804a781 in _start ()
#0  0xffffe410 in __kernel_vsyscall ()