I need to put some bar charts in a ConTeXt document. I'm using mkiv from TeX Live 2011, under Gentoo GNU/Linux. I tried using Gnuplot but I found `mpgraph` suits better my needs.

I'm using this TeX file

```
\usemodule[graph]
\usemodule[sarith]

\enableregime[utf-8]
\starttext

\startMPcode
beginfig(1)
  draw begingraph(12cm,6cm);
    glabel.lft(btex Eje Y etex, OUT);
    glabel.bot(btex Eje X etex, OUT);
    gdata("data.d",
        $,
        path p;
        augment.p (0,$1);
        augment.p ($2,$1);
        augment p ($2,$1 Sadd "1");
        augment p (0,$1 Sadd "1");
        gdraw p withpen pencircle scaled 2bp withcolor red;
    );
  autogrid(grid.bot,grid.lft) withcolor .85white;
  endgraph;
endfig;
\stopMPcode
\stoptext

```

and this data file

```
1 4
2 2
3 1
4 2
5 4

```

as a minimal 'working' example.

However, some strange is happening: I can't use any operator from `sarith` module (used in `mpgraph` module for drawing boxes). I got [this output](http://pastebin.com/7J4gh2KU) with ConTeXt. I tried compiling with Metapost, although I got no errors or warnings the output .dvi is corrupted.

I've tried also with TeX Live 2012 under Windows 7. I can't compile there because of the `sarith` thing, but when I comment that lines it works. But doing the same thing in my Gentoo box works, excepting that text for labels or axis doesn't appear, just a very little square. I don't understand what is happening, even the example from the ConTeXt wiki doesn't work. Clues? Any help is very appreciated!