\foreach and \draw --++ tikz

Question

On my computer, Mac OSX 10.8.5, with texshop, the following code produces only a line between (0,0) and (1,2), like if the loop was ignored. Why?

\documentclass[reqno]{amsart}
\usepackage{amsmath}
\usepackage{tikz}

\begin{document}

\begin{tikzpicture}
\draw (0,0)
    \foreach \x in {1,...,5}
      { --++ (1,2) }
      ;
\end{tikzpicture}

\end{document}

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Thanks for the quick reply!

I did what you said and the version is 2.00

With the command \fill (5,10) circle (2pt); I get the circle at the correct position (5,10).

The code should produce a straight line. Now with the replacement by --++ (\x,2) I get a line from (0,0) to (1,2) and an horizontal line from (1,2) to (5,2).

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In fact I downloaded the pgf version 3.00 but it seems that Tex does not see it since \pgfversion gives always 2.00

I put the downloaded pgf folder (the name was pgf3) in texmf/tex/generic/