Jürgen,
If I can assume by "Print Publisher," you're implying PE, then you'll find the "pstilldll.dll" file under the Arbortext-path\bin folder.If you install the Arbortext Architect, you'll also have the file in the same location on the Architect machine. I don't believe it's installed with the Editor only option.
That file is responsible for building PS/PDF files for the publishing process.
HTH,
Bob