Application that crashed: kmail
Version of the application: 1.12.3
KDE Version: 4.3.3 (KDE 4.3.3)
Qt Version: 4.5.3
Operating System: Linux 2.6.31-sabayon x86_64
Distribution: "Gentoo Base System release 2.0.1"

What I was doing when the application crashed:
after copying kmailrc from the older version, kmail crashed at start (during copy was kmail stoped)

 -- Backtrace:
Application: KMail (kmail), signal: Segmentation fault
[Current thread is 1 (Thread 0x7f022a9a2750 (LWP 14765))]

Thread 2 (Thread 0x7f020d09c910 (LWP 14767)):
#0  0x00007f02274ab24d in pthread_cond_timedwait@@GLIBC_2.3.2 () from /lib/libpthread.so.0
#1  0x00007f0228cab3c2 in QWaitCondition::wait(QMutex*, unsigned long) () from /usr/lib64/qt4/libQtCore.so.4
#2  0x00007f0228ca2713 in ?? () from /usr/lib64/qt4/libQtCore.so.4
#3  0x00007f0228caa683 in ?? () from /usr/lib64/qt4/libQtCore.so.4
#4  0x00007f02274a6624 in start_thread () from /lib/libpthread.so.0
#5  0x00007f02279d456d in clone () from /lib/libc.so.6
#6  0x0000000000000000 in ?? ()

Thread 1 (Thread 0x7f022a9a2750 (LWP 14765)):
[KCrash Handler]
#5  0x00007f02287fdde8 in QTreeWidget::setItemExpanded(QTreeWidgetItem const*, bool) () from /usr/lib64/qt4/libQtGui.so.4
#6  0x00007f0229512d84 in KMail::FolderView::restoreItemStates() () from /usr/lib64/libkmailprivate.so.4
#7  0x00007f0229519327 in KMail::FolderView::reload(bool) () from /usr/lib64/libkmailprivate.so.4
#8  0x00007f0229750d5b in KMMainWidget::readConfig() () from /usr/lib64/libkmailprivate.so.4
#9  0x00007f0229761fdd in KMMainWidget::KMMainWidget(QWidget*, KXMLGUIClient*, KActionCollection*, KConfig*) () from /usr/lib64/libkmailprivate.so.4
#10 0x00007f02294a9749 in ?? () from /usr/lib64/libkmailprivate.so.4
#11 0x00007f02296878a7 in KMKernel::openReader(bool) () from /usr/lib64/libkmailprivate.so.4
#12 0x00007f022968c3e8 in KMKernel::action(bool, bool, QString const&, QString const&, QString const&, QString const&, QString const&, KUrl const&, KUrl::List const&, QStringList const&) ()
   from /usr/lib64/libkmailprivate.so.4
#13 0x00007f022968da89 in KMKernel::handleCommandLine(bool) () from /usr/lib64/libkmailprivate.so.4
#14 0x00000000004039a6 in _start ()

Reported using DrKonqi