Version:           1.7.50 (using KDE 3.3.89 (CVS >= 20040820), compiled sources)
Compiler:          gcc version 3.3.5 (Debian 1:3.3.5-1)
OS:                Linux (i686) release 2.6.9

KMail seems to crash in some mails when filtering my current inbox. It has ~700 messages, and I don't have any idea in which of those it crashes.

That's not so bad, but it duplicates the messages every time it crashes, which isn't very nice.

Anyways, here's the backtrace:
Using host libthread_db library "/lib/tls/i686/cmov/libthread_db.so.1".
[Thread debugging using libthread_db enabled]
[New Thread -1247853824 (LWP 12831)]
[KCrash handler]
#4  0xb7d572aa in KMHeaders::msgRemoved (this=0x82fab18, id=139485488, msgId=
      {static null = {static null = <same as static member of an already seen type>, d = 0x804f070, static shared_null = 0x804f070}, d = 0x8872258, static shared_null = 0x804f070}, strippedSubjMD5=
      {static null = {static null = <same as static member of an already seen type>, d = 0x804f070, static shared_null = 0x804f070}, d = 0x84cb7e8, static shared_null = 0x804f070}) at kmheaders.cpp:1614
#5  0xb7d60341 in KMHeaders::qt_invoke (this=0x82fab18, _id=-1073749744, 
    _o=0xbfffe1c0) at kmheaders.moc:282
#6  0xb60c2884 in QObject::activate_signal ()
   from /home/tpr/kdecvshead/qt-copy/lib/libqt-mt.so.3
#7  0xb7d8dbfc in KMFolder::msgRemoved (this=0x80cebf0, t0=7143529, t1=)
    at kmfolder.moc:249
#8  0xb7d8e4a0 in KMFolder::qt_emit (this=0x80cebf0, _id=-1073749408, 
    _o=0xbfffe310) at kmfolder.moc:369
#9  0xb60c28b9 in QObject::activate_signal ()
   from /home/tpr/kdecvshead/qt-copy/lib/libqt-mt.so.3
#10 0xb7da63fc in FolderStorage::msgRemoved (this=0x8265f90, t0=7143529, t1=)
    at folderstorage.moc:234
#11 0xb7da3977 in FolderStorage::take (this=0x8265f90, idx=145)
    at folderstorage.cpp:408
#12 0xb7e1ba5b in KMFolderImap::take (this=0x8265f90, idx=145)
    at kmfolderimap.cpp:546
#13 0xb7d8be21 in KMFolder::take (this=0x82d3500, idx=7143529)
    at kmfolder.cpp:317
#14 0xb7e38395 in KMFolderMaildir::addMsg (this=0x82742b0, aMsg=0x874b4b0, 
    index_return=0x0) at kmfoldermaildir.cpp:432
#15 0xb7da4061 in FolderStorage::moveMsg (this=0x82742b0, aMsg=0x874b4b0, 
    aIndex_ret=0x6d0069) at folderstorage.cpp:538
#16 0xb7d8bfd8 in KMFolder::moveMsg (this=0x82d3500, msg=0x6d0069, 
    index_return=0x6d0069) at kmfolder.cpp:357
#17 0xb7dd36b7 in KMFilterMgr::process (this=0x82764b8, msg=0x874b4b0, 
    set=Explicit) at kmfiltermgr.cpp:252
#18 0xb7d57986 in KMHeaders::slotFilterMsg (this=0x82fab18, msg=0x874b4b0)
    at kmheaders.cpp:1724
#19 0xb7d6067d in KMHeaders::qt_invoke (this=0x82fab18, _id=135, _o=0xbfffe7d0)
    at kmheaders.moc:305
#20 0xb60c2884 in QObject::activate_signal ()
   from /home/tpr/kdecvshead/qt-copy/lib/libqt-mt.so.3
#21 0xb7ed7957 in KMail::FolderJob::messageRetrieved (this=0x874c370, 
    t0=0x6d0069) at folderjob.moc:129
#22 0xb7ee0a5d in KMail::ImapJob::slotGetMessageResult (this=0x874c370, 
    job=0xcad) at imapjob.cpp:411
#23 0xb7ee1df3 in KMail::ImapJob::qt_invoke (this=0x874c370, _id=2, 
    _o=0xbfffe980) at imapjob.moc:126
#24 0xb60c2884 in QObject::activate_signal ()
   from /home/tpr/kdecvshead/qt-copy/lib/libqt-mt.so.3
#25 0xb6dace78 in KIO::Job::result () from /home/tpr/kdecvshead/lib/libkio.so.4
#26 0xb6d92912 in KIO::Job::emitResult ()
   from /home/tpr/kdecvshead/lib/libkio.so.4
#27 0xb6d9452c in KIO::SimpleJob::slotFinished ()
   from /home/tpr/kdecvshead/lib/libkio.so.4
#28 0xb6d980ef in KIO::TransferJob::slotFinished ()
   from /home/tpr/kdecvshead/lib/libkio.so.4
#29 0xb6daeddb in KIO::TransferJob::qt_invoke ()
   from /home/tpr/kdecvshead/lib/libkio.so.4
#30 0xb60c2884 in QObject::activate_signal ()
   from /home/tpr/kdecvshead/qt-copy/lib/libqt-mt.so.3
#31 0xb60c2651 in QObject::activate_signal ()
   from /home/tpr/kdecvshead/qt-copy/lib/libqt-mt.so.3
#32 0xb6d85afe in KIO::SlaveInterface::finished ()
   from /home/tpr/kdecvshead/lib/libkio.so.4
#33 0xb6d829fe in KIO::SlaveInterface::dispatch ()
   from /home/tpr/kdecvshead/lib/libkio.so.4
#34 0xb6d81b14 in KIO::SlaveInterface::dispatch ()
   from /home/tpr/kdecvshead/lib/libkio.so.4
#35 0xb6d7e898 in KIO::Slave::gotInput ()
   from /home/tpr/kdecvshead/lib/libkio.so.4
#36 0xb6d81067 in KIO::Slave::qt_invoke ()
   from /home/tpr/kdecvshead/lib/libkio.so.4
#37 0xb60c2884 in QObject::activate_signal ()
   from /home/tpr/kdecvshead/qt-copy/lib/libqt-mt.so.3
#38 0xb60c29e7 in QObject::activate_signal ()
   from /home/tpr/kdecvshead/qt-copy/lib/libqt-mt.so.3
#39 0xb6466662 in QSocketNotifier::activated ()
   from /home/tpr/kdecvshead/qt-copy/lib/libqt-mt.so.3
#40 0xb60e25d0 in QSocketNotifier::event ()
   from /home/tpr/kdecvshead/qt-copy/lib/libqt-mt.so.3
#41 0xb605a8ef in QApplication::internalNotify ()
   from /home/tpr/kdecvshead/qt-copy/lib/libqt-mt.so.3
#42 0xb6059eb5 in QApplication::notify ()
   from /home/tpr/kdecvshead/qt-copy/lib/libqt-mt.so.3
#43 0xb67b3d92 in KApplication::notify ()
   from /home/tpr/kdecvshead/lib/libkdecore.so.4
#44 0xb60480c0 in QEventLoop::activateSocketNotifiers ()
   from /home/tpr/kdecvshead/qt-copy/lib/libqt-mt.so.3
#45 0xb5ffafa0 in QEventLoop::processEvents ()
   from /home/tpr/kdecvshead/qt-copy/lib/libqt-mt.so.3
#46 0xb606f8f8 in QEventLoop::enterLoop ()
   from /home/tpr/kdecvshead/qt-copy/lib/libqt-mt.so.3
#47 0xb606f7a8 in QEventLoop::exec ()
   from /home/tpr/kdecvshead/qt-copy/lib/libqt-mt.so.3
#48 0xb605ab51 in QApplication::exec ()
   from /home/tpr/kdecvshead/qt-copy/lib/libqt-mt.so.3
#49 0x0804aa15 in main (argc=7143529, argv=0x6d0069) at main.cpp:108