kubuntu desktop won't start

[BigFlatBrook]

After running gnome for awhile, I want to try out the kubuntu desktop.

I did "sudo apt-get install kubuntu-desktop". It seemed to complete ok because I was asked which desktop I wanted to the the default.

But, the kubuntu desktop won't come up and the error message is

"cannot start kstartconfig" or something similar.

What is kstartconfig? How do I get it? Did I mess up the installation somehow?

Thanks