This is neither a woody, nor a potato or a sid issue. The behaviour of
LaTeX concerning page non-numbering with \pagestyle{empty} and
\thispagestyle{empty} also depends on the other packages which are loaded
at the beginning of the file, some of which can re-initialise page
numbers.
Have a look at the LaTeX FAQ.
Olivier.
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Olivier Crouzet, Ph.D.
Institut des Sciences Cognitives
CNRS - Université Claude Bernard Lyon 1