PGF/TikZ error when using chains

I'm trying to learn how to use PGF/TikZ to draw pictures, in particular a chain of nodes.

I have the following picture:

\begin{tikzpicture}[start chain, node distance=5mm]
\node [on chain,join] {$t_\mathrm{opt flow}$};
\node [on chain,join] {$foo$};
\end{tikzpicture}


I would expect this to yield two nodes connected by a simple line. Instead, when I run LaTex, I get the following error:

./NIQ_Principles.tex:39: Package PGF Math Error: Unknown function of'.
./NIQ_Principles.tex:40: Extra }, or forgotten \endgroup.\endpgfpicture ... \pgf@y }\endgroup \hss \egroup
\pgf@insertlayers \endgrou...


Can someone help me understand what I'm doing wrong?

UPDATE

Here is my complete example:

\documentclass{scrartcl}

\usepackage{tikz}
\usetikzlibrary{chains}

\begin{document}

\begin{tikzpicture} [start chain, node distance=5mm]
\node [on chain,join] {foo};
\node [on chain,join] {bar};
\end{tikzpicture}

\end{document}


And here is the output I get:

ERROR: Package PGF Math Error: Unknown function of'.

--- TeX said ---

See the PGF Math package documentation for explanation.
Type  H <return>  for immediate help.
...

l.10   \node [on chain,join]
{bar};
--- HELP ---
From the .log file...

This error message was generated by an \errmessage
command, so I can't give any explicit help.
Pretend that you're Hercule Poirot: Examine all clues,
and deduce the truth by order and method.


I can't really claim that I'm as smart as Mr Poirot, so can someone point me in the right direction?

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With a ecm "example complete and minimal" perhaps i's possible to give a correct answer. Your example compiles with pgf 2.1 and the library chains (with pdflatex and latex). Do you try an example from the pgfmanual ? you can see if you miss something or see if you need to install a correct version of pgf –  Alain Matthes Jun 12 '11 at 6:35
Package PGF Math Error ? perhaps you have two versions of pgf on your distribution ? –  Alain Matthes Jun 12 '11 at 6:44
@Altermundus I've added a complete example to the question, one that doesn't work on my machine but which is very close to the examples given in the TikZ documentation. –  lindelof Jun 13 '11 at 5:27
your example works with pgf 2.1 cvs without error –  Alain Matthes Jun 13 '11 at 5:49

1 Answer

I found that the pgf package installed under Ubuntu was version 2.00, whereas the latest version (and the one from whose documentation I was trying the examples) was 2.10.

Installing the latest version of pgf under my local texmf tree solved the problem.

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It would be great of you accept your answer by clicking the check mark on the left of the answer. –  Stefan Kottwitz Nov 27 '11 at 18:35