Hi again, @Matej: Thanks. Perhaps the information down there helps you analyze my prolem a little better.
I use MikTeX under Windows with Ghostscript/ImageMagick/etc. I also found put the class paper.cls and it's layout in d:\programme\texmf\tex\latex\base as I did in Linux. Ater taht I turned to MikTeX Options and refreshed the file database AND I reconfiguered Lyx. As result: NOTHING changed ! I don't know what to do now. I thank everyone who has an idea! Best regards Ben
