You need to apt-get Synaptic. It is a GUI software installer for Debian Linux that is better than anything you've ever seen for any other version of Linux, Windows, you name it.

It will tell you in advance if what you want to install is going to cause conflicts and will force it to remove something.

With Synaptic you CAN upgrade whole packages like kdebase etc.

Also, you've discovered the perils of apt-get Upgrade. A no-no with Knoppix. Synaptic is much smarter.

sakiZ