Version:            (using KDE KDE 3.1.4)
Installed from:    Compiled From Sources
Compiler:          g++-3.3 (GCC) 3.3.2 (Debian) (rebuilt kdenetwork package from debian sources with g++ 3.3.2, nostrip/debug)
OS:          Linux

(I have filed a new bug because it is not clear which of the existing bugs is most similar.  Hopefully the attached backtrace is of some use.)

System:  Debian sid on powerpc
IMAP:  courier imapd 0.42.2 (backport to woody on i386)

My KMail sometimes crashes when indexing an IMAP folder (courier imapd 0.42.2), generally in response to either clicking on the folder or moving a message from one folder to another on the IMAP server.  The packaged version on Debian sid did not produce a useful backtrace, so I rebuilt from the Debian packaged sources using DEB_BUILD_OPTIONS="debug nostrip" and gcc/g++ 3.3.2 (the Debian g++-3.3 package, not g++, which is still at 3.3.1).  The resulting backtrace is attached.

I would be happy to experiment with other build variations if that would be helpful.  (I don't know enough about the structure of the KDE code base to guess whether the bug is really in KMail or in one of the underlying libraries.)  I'll start by rebuilding kdelibs, and I'll also try on i386.

[New Thread 16384 (LWP 22407)]
0x3023bfdc in waitpid () from /lib/libpthread.so.0
#0  0x3023bfdc in waitpid () from /lib/libpthread.so.0
#1  0x0f12c170 in KCrash::defaultCrashHandler(int) ()
   from /usr/lib/libkdecore.so.4
#2  0x3023aa00 in __pthread_sighandler () from /lib/libpthread.so.0
#3  <signal handler called>
#4  0x30560a70 in kill () from /lib/libc.so.6
#5  0x302377d8 in pthread_kill () from /lib/libpthread.so.0
#6  0x30237c54 in raise () from /lib/libpthread.so.0
#7  0x30560858 in raise () from /lib/libc.so.6
#8  0x30561f34 in abort () from /lib/libc.so.6
#9  0x0f0c8b60 in KApplication::qt_static_property(QObject*, int, int, QVariant*) () from /usr/lib/libkdecore.so.4
#10 0x0f0c9730 in kdbgstream::flush() () from /usr/lib/libkdecore.so.4
#11 0x10045254 in endl (s=@0x3066fb08) at kdebug.h:178
#12 0x0f96e57c in KMime::Codec::decode(QMemArray<char> const&, bool) const (
    this=0x3066fb08, src=@0x7fffdaf8, withCRLF=36) at kdebug.h:206
#13 0x10172a2c in KMMsgBase::decodeRFC2047String(QCString const&) (
    aStr=@0xf1e7f5c) at ../../kmail/kmmsgbase.cpp:431
#14 0x1003b0a8 in KMMessage::headerField(QCString const&) const (this=0x6, 
    aName=@0x105ad6b8) at string.h:64
#15 0x1003a2bc in KMMessage::fromStrip() const (this=0x7fffee18)
    at ../../kmail/kmmessage.cpp:1651
#16 0x1013ab70 in KMMsgInfo::operator=(KMMessage const&) (this=0x105ee638, 
    msg=@0x104ffae0) at ../../kmail/kmmsginfo.cpp:130
#17 0x100ff878 in KMFolder::unGetMsg(int) (this=0x10250000, idx=122)
    at ../../kmail/kmfolder.cpp:950
#18 0x101993f4 in KMFolderImap::slotGetMessagesData(KIO::Job*, QMemArray<char> const&) (this=0x103afe38, job=0x30560a68, data=@0x222)
    at ../../kmail/kmfolderimap.cpp:908
#19 0x101a0808 in KMFolderImap::qt_invoke(int, QUObject*) (this=0x103afe38, 
    _id=25, _o=0x7ffff088) at qucom_p.h:312
#20 0x0eae62b0 in QObject::activate_signal(QConnectionList*, QUObject*) ()
   from /usr/lib/libqt-mt.so.3
#21 0x0f5d6f64 in KIO::TransferJob::data(KIO::Job*, QMemArray<char> const&) ()
   from /usr/lib/libkio.so.4
#22 0x0f5c6c18 in KIO::TransferJob::slotData(QMemArray<char> const&) ()
   from /usr/lib/libkio.so.4
#23 0x0f5d759c in KIO::TransferJob::qt_invoke(int, QUObject*) ()
   from /usr/lib/libkio.so.4
#24 0x0eae62b0 in QObject::activate_signal(QConnectionList*, QUObject*) ()
   from /usr/lib/libqt-mt.so.3
#25 0x0f5b9384 in KIO::SlaveInterface::data(QMemArray<char> const&) ()
   from /usr/lib/libkio.so.4
#26 0x0f5b7a20 in KIO::SlaveInterface::dispatch(int, QMemArray<char> const&) ()
   from /usr/lib/libkio.so.4
#27 0x0f5b7758 in KIO::SlaveInterface::dispatch() () from /usr/lib/libkio.so.4
#28 0x0f5b5550 in KIO::Slave::gotInput() () from /usr/lib/libkio.so.4
#29 0x0f5b6d48 in KIO::Slave::qt_invoke(int, QUObject*) ()
   from /usr/lib/libkio.so.4
#30 0x0eae62b0 in QObject::activate_signal(QConnectionList*, QUObject*) ()
   from /usr/lib/libqt-mt.so.3
#31 0x0eae6430 in QObject::activate_signal(int, int) ()
   from /usr/lib/libqt-mt.so.3
#32 0x0ee0e8b4 in QSocketNotifier::activated(int) ()
   from /usr/lib/libqt-mt.so.3
#33 0x0eb02968 in QSocketNotifier::event(QEvent*) ()
   from /usr/lib/libqt-mt.so.3
#34 0x0ea841d0 in QApplication::internalNotify(QObject*, QEvent*) ()
   from /usr/lib/libqt-mt.so.3
#35 0x0ea83964 in QApplication::notify(QObject*, QEvent*) ()
   from /usr/lib/libqt-mt.so.3
#36 0x0f0ba690 in KApplication::notify(QObject*, QEvent*) ()
   from /usr/lib/libkdecore.so.4
#37 0x0ea7212c in QEventLoop::activateSocketNotifiers() ()
   from /usr/lib/libqt-mt.so.3
#38 0x0ea2ed18 in QEventLoop::processEvents(unsigned) ()
   from /usr/lib/libqt-mt.so.3
#39 0x0ea98dfc in QEventLoop::enterLoop() () from /usr/lib/libqt-mt.so.3
#40 0x0ea98c08 in QEventLoop::exec() () from /usr/lib/libqt-mt.so.3
#41 0x0ea84464 in QApplication::exec() () from /usr/lib/libqt-mt.so.3
#42 0x101bb744 in main (argc=2147479352, argv=0x7b) at kapplication.h:178

KDE package versions:
ii  kde-core       3.1.1          The K Desktop Environment (Core)
ii  kdeaddons      3.1.4-1        add-on plugins and applets provided with KDE
ii  kdeaddons-kfil 3.1.4-1        KDE file dialog plugins for text files and f
ii  kdeadmin       3.1.4-1        KDE Administration tools metapackage
ii  kdeadmin-kfile 3.1.4-1        KDE File dialog plugins for deb and rpm file
ii  kdeartwork     3.1.4-1        themes, styles and more from the official KD
ii  kdeartwork-mis 3.1.4-1        various multimedia goodies released with KDE
ii  kdeartwork-sty 3.1.4-1        widget styles released with KDE
ii  kdeartwork-the 3.1.4-1        icon themes released with KDE
ii  kdeartwork-the 3.1.4-1        window decoration themes released with KDE
ii  kdebase        3.1.3-1        KDE Base metapackage
ii  kdebase-bin    3.1.3-1        KDE Base (binaries)
ii  kdebase-data   3.1.3-1        KDE Base (shared data)
ii  kdebase-kio-pl 3.1.3-1        KDE I/O Slaves
ii  kdelibs        3.1.4-3        KDE core libraries metapackage
ii  kdelibs-bin    3.1.4-3        KDE core binaries
ii  kdelibs-data   3.1.4-3        KDE core shared data
ii  kdelibs4       3.1.4-3        KDE core libraries
ii  kdelibs4-dev   3.1.4-3        KDE core libraries (development files)
ii  kdenetwork     3.1.4-1        KDE Network metapackage
ii  kdenetwork-kfi 3.1.4-1        KFile Email Plugin
ii  kdepasswd      3.1.4-1        KDE password changer
ii  kdepim-libs    3.1.4-1        KDE PIM libraries
ii  kdeprint       3.1.3-1        KDE Print
ii  kdesktop       3.1.3-1        KDE Desktop
ii  kdessh         3.1.4-1        KDE ssh frontend
ii  kdeutils       3.1.4-1        KDE Utilities metapackage
ii  kdewallpapers  3.1.4-1        wallpapers released with KDE
ii  libkdenetwork2 3.1.4-1        KDE Network (common libraries)
ii  libkdenetwork2 3.1.4-1        KDE Network (development files)