tikz: Position of text wrong

Dear pgf/tikz users,

I am newbie in tikz and encounter problems using tikz while running the
following example from pgfmanual.pdf, page 33

\begin{tikzpicture}
  \foreach \x in {1,2,...,5,7,8,...,12}
    \foreach \y in {1,...,5}
    {
      \draw (\x,\y) +(-.5,-.5) rectangle ++(.5,.5);
      \draw (\x,\y) node{\x,\y};
    }
\end{tikzpicture}

The text is not printed in the rectangles but rather in at the bottom left of
the picture (looks like all the numbers over each other).

I use the LaTeX environment from openSUSE 11.1:

Do you have any idea what I am doing wrong?

Best regards
Udo

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