# PSTricks error “Undefined control sequence <recently read> \c@lor@to@ps”

I have a problem with this file tex:

\begin{document}
\begin{figure}
\begin{center}
\begin{pspicture}(0,0)(1,3.8)
\psline{-<}(0,0)(0,.2)
\psline{-}(0,.2)(0,.4)
\psline{*->}(0,.4)(0,.9)
\psline{-*}(0,.9)(0,1.4)
\psline{-<}(0,1.4)(0,2.4)
\psline{-}(0,2.4)(0,3.4)
\psline{*-}(0,3.4)(0,3.6)
\psline{>-}(0,3.6)(0,3.8)
\rput(1,.4){$y=0$}%testo
\rput(1,1.4){$y=1$}
\rput(1,3.4){$y=3$}
\end{pspicture}
\end{center}
\caption{}
\end{figure}
\end{document}


but I don't understand where is the error.

-
Welcome to TeX.sx! A tip: If you indent lines by 4 spaces, they'll be marked as a code sample. You can also highlight the code and click the "code" button (with "{}" on it). I think we will need a full minimal working example (MWE) including your preamble. –  Joseph Wright Aug 26 '12 at 15:54
It is not related to your problem but it is worth mentioning that it is recommended to use \centering instead of \begin{center}...\end{center}. –  I am who I say I am Aug 26 '12 at 16:00
Was there an error message? –  LarsH Aug 7 '13 at 17:27
It is the typical error message when using pdflatex with PSTricks.
Run the document with xelatex or use the sequence latex->dvips->ps2pdf (which is often only one click in a GUI). See also FDE no 4 (Frequently Done Error) at http://PSTricks.tug.org