KDE 4 packages are currently in the experimental branch and are not intended to be installed on a production system. We are not accepting bug reports against the KDE 4 packages at the moment, since they have many known problems.
If you run into a problem and need help, you can send a mail to the Debian KDE support list. The list is not moderated, so you can post without subscribing.
If you want to help us get KDE 4 ready, you're welcome to join the team!