[texworks] packages not found

[Alain Delmotte]

Hi!

If I try this CME in TeXworks:
------------------------------------
\documentclass{minimal}
\usepackage{tikz}
\usetikzlibrary{hobby}
\begin{document}
\begin{tikzpicture}
\draw (0,0) to[curve through={(6,4) .. (4,9) .. (1,7)}] (3,5);
\end{tikzpicture}
\end{document}
------------------------------------

I got an error, the hobby package is not found:

------------------------------------
(c:/texlive/2011/texmf-dist/tex/generic/pgf/frontendlayer/tikz/libraries/tikzli
brarytopaths.code.tex)))
! I can't find file `tikzlibraryhobby.code.tex'.
<argument> ...nput tikzlibrary\pgf at temp .code.tex
                                                   \catcode 
`\@ =\csname tikz...
l.3 \usetikzlibrary{hobby}

(Press Enter to retry, or Control-Z to exit)
Please type another input file name
! Emergency stop.
<argument> ...nput tikzlibrary\pgf at temp .code.tex
                                                   \catcode 
`\@ =\csname tikz...
l.3 \usetikzlibrary{hobby}

!  ==> Fatal error occurred, no output PDF file produced!
Transcript written on LaTeX4.log.
------------------------------------

But if I compile it with TeXmaker, it works!!!

Why is the hobby package not found by TeXworks?

I have
C:/texlive/2012/bin/win32
C:/texlive/2012/bin
in the path of TeXworks

hobby is in
C:\texlive\2012\texmf-dist\tex\latex\hobby where one can 
find tikzlibraryhobby.code.tex, pgflibraryhobby.code.tex and 
hobby.code.tex (as well as pml3array.sty).

Regards,

Alain