Kmail in 11.4 VERY slow

Hi there,
I am using 11.4 for quite a while (very happy with it). Now kmail is making trouble: as soon as I start it up upon login, it takes minutes to react to any input (e. g. switching of inboxes, scrolling through mails, etc.).

I started kmail via terminal, here is what it spat out:

KGlobal::locale::Warning your global KLocale is being recreated with a valid main component instead of a fake component, this usually means you tried to call i18n related functions before your main component was created. You should not do that since it most likely will not work
kmail(8467) KMFolderMgr::removeFolderAux: Can not find parent folder for Last Search
user@linux:~> kmail(8467)/kio (KIOJob) KIO::TransferJob::slotData: mimeType() not emitted when sending first data!; job URL = KUrl(“pop3://email@post.com:110/index”) data size = 0
kmail(8467)/kio (KIOJob) KIO::TransferJob::slotData: mimeType() not emitted when sending first data!; job URL = KUrl(“pop3://email@post.com:110/uidl”) data size = 0
QPainter::begin: Widget painting can only begin as a result of a paintEvent
QPainter::translate: Painter not active
QPainter::setClipRect: Painter not active

Any idea what is wrong?

Many thanks,
Knut