Application that crashed: kmail
Version of the application: 1.12.0
KDE Version: 4.2.95 (KDE 4.2.95 (KDE 4.3 RC1))
Qt Version: 4.5.2
Operating System: Linux 2.6.24.7 i686

What I was doing when the application crashed:
When I open a message with an attachment and press reply the new composer opens. I then press send for the first time - this press is ignored. Pressing send for the second time sends the message (successfully most of the time, sometimes it stays in the outbox) but shortly afterwards kmail crashes. 
To avoid I have to enter some characters in one of the recipient fields (BCC, CC, TO) and wait for a completion to happen.

 -- Backtrace:
Application: KMail (kmail), signal: Segmentation fault
[Current thread is 0 (LWP 5144)]

Thread 3 (Thread 0xb0c36b90 (LWP 5366)):
#0  0xffffe410 in __kernel_vsyscall ()
#1  0x4116ab82 in pthread_cond_timedwait@@GLIBC_2.3.2 () from /lib/libpthread.so.0
#2  0xb6829674 in QWaitCondition::wait () from /usr/lib/qt4/libQtCore.so.4
#3  0xb682065c in ?? () from /usr/lib/qt4/libQtCore.so.4
#4  0x086bfd38 in ?? ()
#5  0x086bfd34 in ?? ()
#6  0x00007530 in ?? ()
#7  0xb6828e66 in ?? () from /usr/lib/qt4/libQtCore.so.4
#8  0x0829e698 in ?? ()
#9  0x00000001 in ?? ()
#10 0x0829e698 in ?? ()
#11 0xb694f167 in QThread::started () from /usr/lib/qt4/libQtCore.so.4
#12 0xb6828fc7 in ?? () from /usr/lib/qt4/libQtCore.so.4
#13 0x08790fa8 in ?? ()
#14 0x00000000 in ?? ()

Thread 2 (Thread 0xaed6bb90 (LWP 5370)):
#0  0xffffe410 in __kernel_vsyscall ()
#1  0x4116ab82 in pthread_cond_timedwait@@GLIBC_2.3.2 () from /lib/libpthread.so.0
#2  0xb6829674 in QWaitCondition::wait () from /usr/lib/qt4/libQtCore.so.4
#3  0xb682065c in ?? () from /usr/lib/qt4/libQtCore.so.4
#4  0x086bfd38 in ?? ()
#5  0x086bfd34 in ?? ()
#6  0x00007530 in ?? ()
#7  0xb6828e66 in ?? () from /usr/lib/qt4/libQtCore.so.4
#8  0x08696810 in ?? ()
#9  0x00000001 in ?? ()
#10 0xaed6b318 in ?? ()
#11 0xb694f167 in QThread::started () from /usr/lib/qt4/libQtCore.so.4
#12 0xb6828fc7 in ?? () from /usr/lib/qt4/libQtCore.so.4
#13 0x0829ead8 in ?? ()
#14 0x00000000 in ?? ()

Thread 1 (Thread 0xb4373700 (LWP 5144)):
[KCrash Handler]
#6  0xb76663e9 in RecipientsEditor::recipientString (this=0x636e7566, type=Recipient::Cc) at /root/kdesvn-4.3/kdepim/kmail/recipientseditor.cpp:947
#7  0xb736c76b in KMComposeWin::cc (this=0x86c1f50) at /root/kdesvn-4.3/kdepim/kmail/kmcomposewin.cpp:1398
#8  0xb73864dd in KMComposeWin::doSend (this=0x86c1f50, method=KMail::MessageSender::SendImmediate, saveIn=KMComposeWin::None) at /root/kdesvn-4.3/kdepim/kmail/kmcomposewin.cpp:3494
#9  0xb7387f35 in KMComposeWin::slotSendNow (this=0x86c1f50) at /root/kdesvn-4.3/kdepim/kmail/kmcomposewin.cpp:3780
#10 0xb7388aa1 in KMComposeWin::qt_metacall (this=0x86c1f50, _c=QMetaObject::InvokeMetaMethod, _id=11, _a=0xbf918cac) at /root/kdesvn-4.3/build/kdepim/kmail/kmcomposewin.moc:240
#11 0xb691811f in QMetaObject::activate () from /usr/lib/qt4/libQtCore.so.4
#12 0xb6918430 in QMetaObject::activate () from /usr/lib/qt4/libQtCore.so.4
#13 0xb5fdb1a1 in QAction::triggered () from /usr/lib/qt4/libQtGui.so.4
#14 0xb5fdc343 in QAction::activate () from /usr/lib/qt4/libQtGui.so.4
#15 0xb640e9d2 in QToolButton::nextCheckState () from /usr/lib/qt4/libQtGui.so.4
#16 0xb6343d3f in ?? () from /usr/lib/qt4/libQtGui.so.4
#17 0x08928a58 in ?? ()
#18 0xb669aff4 in ?? () from /usr/lib/qt4/libQtGui.so.4
#19 0xbf918d28 in ?? ()
#20 0xb69053d4 in QBasicTimer::stop () from /usr/lib/qt4/libQtCore.so.4
#21 0xb6343fa8 in QAbstractButton::mouseReleaseEvent () from /usr/lib/qt4/libQtGui.so.4
#22 0xb640eacc in QToolButton::mouseReleaseEvent () from /usr/lib/qt4/libQtGui.so.4
#23 0xb6035708 in QWidget::event () from /usr/lib/qt4/libQtGui.so.4
#24 0xb6343213 in QAbstractButton::event () from /usr/lib/qt4/libQtGui.so.4
#25 0xb641152e in QToolButton::event () from /usr/lib/qt4/libQtGui.so.4
#26 0xb5fe189f in QApplicationPrivate::notify_helper () from /usr/lib/qt4/libQtGui.so.4
#27 0xb5fe8602 in QApplication::notify () from /usr/lib/qt4/libQtGui.so.4
#28 0xb7d5c802 in KApplication::notify (this=0xbf91abfc, receiver=0x8928a58, event=0xbf9193c0) at /root/kdesvn-4.3/kdelibs/kdeui/kernel/kapplication.cpp:302
#29 0xb69063c8 in QCoreApplication::notifyInternal () from /usr/lib/qt4/libQtCore.so.4
#30 0xb5fe9ab0 in QApplicationPrivate::sendMouseEvent () from /usr/lib/qt4/libQtGui.so.4
#31 0xb60487d0 in ?? () from /usr/lib/qt4/libQtGui.so.4
#32 0x08928a58 in ?? ()
#33 0xbf9193c0 in ?? ()
#34 0x08928a58 in ?? ()
#35 0x086c1f50 in ?? ()
#36 0xb669da60 in ?? () from /usr/lib/qt4/libQtGui.so.4
#37 0xb669da64 in ?? () from /usr/lib/qt4/libQtGui.so.4
#38 0xbf91946c in ?? ()
#39 0xb669aff4 in ?? () from /usr/lib/qt4/libQtGui.so.4
#40 0xbf919384 in ?? ()
#41 0xb669aff4 in ?? () from /usr/lib/qt4/libQtGui.so.4
#42 0xbf919948 in ?? ()
#43 0xb622096d in ?? () from /usr/lib/qt4/libQtGui.so.4
#44 0xbf919424 in ?? ()
#45 0xbf91942c in ?? ()
#46 0x003d3047 in ?? ()
#47 0x00000003 in ?? ()
#48 0x00000001 in ?? ()
#49 0xbf919908 in ?? ()
#50 0xbf9198c8 in ?? ()
#51 0x00000040 in ?? ()
#52 0x41156160 in ?? () from /lib/libc.so.6
#53 0x4108a6a4 in ?? () from /lib/libc.so.6
#54 0x00000000 in ?? ()

Reported using DrKonqi