Version:           2.1 (using KDE KDE 3.5.7)
Installed from:    Debian stable Packages
OS:                Linux

First of all, I use Kubuntu 7.04 (Feisty Fawn) and updated yesterday to a new version of KTorrent (I don't know the old version, but it was a long-known issue with the [k]ubuntu-guys) and was happy about it, because KTorrent crashed very often. I had restarted my PC and all seemed well, but when I wanted to start KTorrent, it crashed right at the beginning (four or five times). When I wanted to reproduce the error  for this error for this error-reprt, it started normally for the first time!

Here's the output of the KDE-Crashmanager:
(no debugging symbols found)
Using host libthread_db library "/lib/tls/i686/cmov/libthread_db.so.1".
(no debugging symbols found) (snipped 33x)
[Thread debugging using libthread_db enabled]
[New Thread -1235732784 (LWP 8895)]
(no debugging symbols found) (snipped 47x)
[KCrash handler]
#6  0xb7ddebcb in dht::ParseRsp () from /usr/lib/libktorrent-2.1.so
#7  0xb7ddedf2 in dht::MakeRPCMsg () from /usr/lib/libktorrent-2.1.so
#8  0xb7dd3f51 in dht::RPCServer::readPacket ()
   from /usr/lib/libktorrent-2.1.so
#9  0xb7dd4252 in dht::RPCServer::qt_invoke ()
   from /usr/lib/libktorrent-2.1.so
#10 0xb6e1888b in QObject::activate_signal () from /usr/lib/libqt-mt.so.3
#11 0xb6e19330 in QObject::activate_signal () from /usr/lib/libqt-mt.so.3
#12 0xb75a204c in KNetwork::KClientSocketBase::readyRead ()
   from /usr/lib/libkdecore.so.4
#13 0xb75a2086 in KNetwork::KClientSocketBase::slotReadActivity ()
   from /usr/lib/libkdecore.so.4
#14 0xb75b4143 in KNetwork::KClientSocketBase::qt_invoke ()
   from /usr/lib/libkdecore.so.4
#15 0xb75b41e6 in KNetwork::KDatagramSocket::qt_invoke ()
   from /usr/lib/libkdecore.so.4
#16 0xb6e1888b in QObject::activate_signal () from /usr/lib/libqt-mt.so.3
#17 0xb6e191a2 in QObject::activate_signal () from /usr/lib/libqt-mt.so.3
#18 0xb71a5877 in QSocketNotifier::activated () from /usr/lib/libqt-mt.so.3
#19 0xb6e3b44a in QSocketNotifier::event () from /usr/lib/libqt-mt.so.3
#20 0xb6dafa60 in QApplication::internalNotify () from /usr/lib/libqt-mt.so.3
#21 0xb6db188f in QApplication::notify () from /usr/lib/libqt-mt.so.3
#22 0xb7573ce2 in KApplication::notify () from /usr/lib/libkdecore.so.4
#23 0xb6d421e9 in QApplication::sendEvent () from /usr/lib/libqt-mt.so.3
#24 0xb6da1e59 in QEventLoop::activateSocketNotifiers ()
   from /usr/lib/libqt-mt.so.3
#25 0xb6d56d07 in QEventLoop::processEvents () from /usr/lib/libqt-mt.so.3
#26 0xb6dca136 in QEventLoop::enterLoop () from /usr/lib/libqt-mt.so.3
#27 0xb6dc9f46 in QEventLoop::exec () from /usr/lib/libqt-mt.so.3
#28 0xb6db1609 in QApplication::exec () from /usr/lib/libqt-mt.so.3
#29 0x080653d6 in ?? ()
#30 0xb65c9ebc in __libc_start_main () from /lib/tls/i686/cmov/libc.so.6
#31 0x08064ec1 in ?? ()
------------------------
I just checked: #1 to #5 are not in the crash-report. I REALLY just snipped the multiple "no debugging symbols found". 
I just started KTorrent again and it works good. It is a bit spooky, as if it knew I am filing a bug report, but I thought you should know. I'll watch it and report in a few days again.