Liviu, Thanks, all it says is
+Read the file doc/LaTeXConfig.lyx for more information. gra...@eeepc-linux:~$ lyx Error: Couldn't export file ---------------------------------------- No information for exporting the format PDF (pdflatex). If I just use article class it compiles OK, its just when I change the class to article Sweave noweb that I get the error, so it seems an Sweave issue. Graham