KDE Upgrade to 3.0

I just found this at the KDE site. Maybe it is the reason that you have not
yet been successful? I don't have time to try it this morning but I will
tonight or tomorrow.

http://download.at.kde.org/pub/kde/stable/3.0/Red Hat/README

I says you should delete the previous version RPMs before installing the new
ones and has the command lines to use.

Alan