First, do not use Yast2 to upgrade to KDE 3.1. It would not install all the packages, I found using rpm much easier.
Have you downloaded all the packages you need? I do not why, but SuSE puts some packages that I would consider "BASE" packages in the applications directory.
An example of the is kdenetwork3. I would review the applications directory for all kde* packages that you need and download and install them.
You should be all set then.