Q: about \externalfile from metafun-p.pdf

[Alexander Lazic <al-context@none.at>]

Hi,

i'm starting to learn context and therefore i have copied some examples
from metafun-p.pdf and get the following error:

---
! Undefined control sequence.
l.42 \externalfile
                  [mprun.21][width=5cm]
---
---
texexec  --version

 TeXExec 5.4.3 - ConTeXt / PRAGMA ADE 1997-2005

               texexec : TeXExec 5.4.3 - ConTeXt / PRAGMA ADE 1997-2005
               texutil : TeXUtil 9.0.0 - ConTeXt / PRAGMA ADE 1992-2004
                   tex : pdfeTeX, 3.141592-1.30.3-2.2 (Web2C 7.5.5)
               context : ver: 2005.07.27
               cont-en : ver: 2005.07.27  fmt: 2005.10.1  mes: english

        total run time : 2 seconds
---
The context code:

---
\language[de]

\setupcolors[state=start]
\setupoutput[pdftex]
\setuppapersize[A4][A4]

\setuppagenumbering[location={footer,right}]
\setupfootertexts[][{Seite \pagenumber{} von \totalnumberofpages}]

\starttext
% in the metapost_test is the code from page 118 => beginfig(21) ;...
\startMPrun
  input metapost_test;
\stopMPrun

\externalfile[mprun.21][width=5cm]

\showsetups
\showlayout
\stoptext
---

Please can any body help, thx.

al ;-)