Sweave doesn't work

Sweave("example.Rtex") in R it seems working

[...]

<*> ...le/Desktop/dati/LaTeX1.Rtex*

Sounds like you are first running sweave on the file 'example.Rtex'
and later LaTex on 'LaTeX1.Rtex'

Two points:

1) why do these files have totally differnt names? If the Sweave file
was called 'example.Rtex' I'd expect the corresponding LaTex file to
be 'example.tex'

2) Why to both files have the same extension? Commonly, the Sweave
files are called 'something.Snw' or 'something.Rnw' and the resulting
LaTex Files would be 'something.tex'

cu
	Philipp