Version:           1.8 (using KDE 3.4.0 Level "a" , SUSE 9.2 UNSUPPORTED)
Compiler:          gcc version 3.3.4 (pre 3.3.5 20040809)
OS:                Linux (i686) release 2.6.8-24.16-default

I just used the expire function for one folder and then the below happened:

Using host libthread_db library "/lib/tls/libthread_db.so.1".
[Thread debugging using libthread_db enabled]
[New Thread 1105419840 (LWP 15360)]
[KCrash handler]
#7  0x084418dc in ?? ()
#8  0x4267bfec in KMMoveCommand::execute ()
   from /opt/kde3/lib/libkmailprivate.so
#9  0x426c81c9 in KMCommand::slotPostTransfer ()
   from /opt/kde3/lib/libkmailprivate.so
#10 0x426c8287 in KMCommand::qt_invoke ()
   from /opt/kde3/lib/libkmailprivate.so
#11 0x426c86bb in KMMenuCommand::qt_invoke ()
   from /opt/kde3/lib/libkmailprivate.so
#12 0x426c8721 in KMMoveCommand::qt_invoke ()
   from /opt/kde3/lib/libkmailprivate.so
#13 0x4154d31e in QObject::activate_signal ()
   from /usr/lib/qt3/lib/libqt-mt.so.3
#14 0x42601d52 in KMCommand::messagesTransfered ()
   from /opt/kde3/lib/libkmailprivate.so
#15 0x4268722a in KMCommand::transferSelectedMsgs ()
   from /opt/kde3/lib/libkmailprivate.so
#16 0x4268784b in KMCommand::slotStart ()
   from /opt/kde3/lib/libkmailprivate.so
#17 0x426c8294 in KMCommand::qt_invoke ()
   from /opt/kde3/lib/libkmailprivate.so
#18 0x426c86bb in KMMenuCommand::qt_invoke ()
   from /opt/kde3/lib/libkmailprivate.so
#19 0x426c8721 in KMMoveCommand::qt_invoke ()
   from /opt/kde3/lib/libkmailprivate.so
#20 0x4154d31e in QObject::activate_signal ()
   from /usr/lib/qt3/lib/libqt-mt.so.3
#21 0x4189f132 in QSignal::signal () from /usr/lib/qt3/lib/libqt-mt.so.3
#22 0x4156a873 in QSignal::activate () from /usr/lib/qt3/lib/libqt-mt.so.3
#23 0x415722c3 in QSingleShotTimer::event ()
   from /usr/lib/qt3/lib/libqt-mt.so.3
#24 0x414eabaf in QApplication::internalNotify ()
   from /usr/lib/qt3/lib/libqt-mt.so.3
#25 0x414ec773 in QApplication::notify () from /usr/lib/qt3/lib/libqt-mt.so.3
#26 0x41175631 in KApplication::notify () from /opt/kde3/lib/libkdecore.so.4
#27 0x414df35c in QEventLoop::activateTimers ()
   from /usr/lib/qt3/lib/libqt-mt.so.3
#28 0x41498156 in QEventLoop::processEvents ()
   from /usr/lib/qt3/lib/libqt-mt.so.3
#29 0x41502b41 in QEventLoop::enterLoop () from /usr/lib/qt3/lib/libqt-mt.so.3
#30 0x41502986 in QEventLoop::exec () from /usr/lib/qt3/lib/libqt-mt.so.3
#31 0x414ec63f in QApplication::exec () from /usr/lib/qt3/lib/libqt-mt.so.3
#32 0x08063ca5 in main ()