Version:           1.9.1 (using KDE 3.5.2, Kubuntu Package 4:3.5.2-0ubuntu18.1 dapper)
Compiler:          Target: i486-linux-gnu
OS:                Linux (i686) release 2.6.15-26-386

Not reproducable: When I pressed "r" for replying to an email I got a crash:

[KCrash handler]
#6  0xb548875e in KMMessage::headerField () from /usr/lib/libkmailprivate.so
#7  0xb5496d91 in KMMessage::identityUoid () from /usr/lib/libkmailprivate.so
#8  0xb5496fad in KMMessage::initFromMessage ()
   from /usr/lib/libkmailprivate.so
#9  0xb5499eea in KMMessage::createReply () from /usr/lib/libkmailprivate.so
#10 0xb5677d04 in KMReplyToCommand::execute ()
   from /usr/lib/libkmailprivate.so
#11 0xb566f162 in KMCommand::slotPostTransfer ()
   from /usr/lib/libkmailprivate.so
#12 0xb5674bbf in KMCommand::qt_invoke () from /usr/lib/libkmailprivate.so
#13 0xb567524b in KMReplyToCommand::qt_invoke ()
   from /usr/lib/libkmailprivate.so
#14 0xb70e2051 in QObject::activate_signal () from /usr/lib/libqt-mt.so.3
#15 0xb566e13c in KMCommand::messagesTransfered ()
   from /usr/lib/libkmailprivate.so
#16 0xb5674771 in KMCommand::transferSelectedMsgs ()
   from /usr/lib/libkmailprivate.so
#17 0xb56749c9 in KMCommand::slotStart () from /usr/lib/libkmailprivate.so
#18 0xb5674bd1 in KMCommand::qt_invoke () from /usr/lib/libkmailprivate.so
#19 0xb567524b in KMReplyToCommand::qt_invoke ()
   from /usr/lib/libkmailprivate.so
#20 0xb70e2051 in QObject::activate_signal () from /usr/lib/libqt-mt.so.3
#21 0xb7475432 in QSignal::signal () from /usr/lib/libqt-mt.so.3
#22 0xb70ff7c8 in QSignal::activate () from /usr/lib/libqt-mt.so.3
#23 0xb71072b8 in QSingleShotTimer::event () from /usr/lib/libqt-mt.so.3
#24 0xb7077f3e in QApplication::internalNotify () from /usr/lib/libqt-mt.so.3
#25 0xb707813a in QApplication::notify () from /usr/lib/libqt-mt.so.3
#26 0xb7775d7d in KApplication::notify () from /usr/lib/libkdecore.so.4
#27 0xb7009157 in QApplication::sendEvent () from /usr/lib/libqt-mt.so.3
#28 0xb706992b in QEventLoop::activateTimers () from /usr/lib/libqt-mt.so.3
#29 0xb701cf67 in QEventLoop::processEvents () from /usr/lib/libqt-mt.so.3
#30 0xb7090a2f in QEventLoop::enterLoop () from /usr/lib/libqt-mt.so.3
#31 0xb7090952 in QEventLoop::exec () from /usr/lib/libqt-mt.so.3
#32 0xb7076a4d in QApplication::exec () from /usr/lib/libqt-mt.so.3
#33 0x0805ab01 in ?? ()