[pstricks] displaying parts of tree in beamer with pstree

[A. Erhardt]

Uuuups, 

forget it, I saw it, big SORRY!
Angelika Erhardt




Hello, Pstrickers,

I keep learning interesting stuff just by being subscibed to the list and reading the contributions
which are of interest for me.

The treestuff with beamer interests me very much,  so I pdfLatexed Herbert Voss's text below.
Surprisingly, I got some black pages (enclosed please find the *.tex and the pdf document).
Sounds like some outdated packages. I am using Miktex2.6 (not yet ready to convert to Miktex2.7!)

Any ideas anybody?
Thanks in advance
Angelika Erhardt