Why does stmt, label(btex Au dessus  etex, (0,0));
fail when using stmt, \DeclareGraphicsRule{*}{mps}{*}{}
but works with stmt, \DeclareGraphicsRule{*}{eps}{*}{}

I am running texlive/2010.


Here is the error msg I get when using mps.

>/usr/local/texlive/2010/bin/i386-linux/mpost xtest.mp
This is MetaPost, version 1.211 (TeX Live 2010) (kpathsea version 6.0.0)
(./xtest.mpfatal: Command failed: etex --parse-first-line
--interaction=nonstopmode mpIYqrrH.tex; see mpxerr.log
>> xtest.mp
>> xtest.mpx
! Unable to make mpx file.
l.15 label(btex
                Au dessus  etex, (0,0));
Transcript written on xtest.log.




-- xtext.mp
%
verbatimtex
%&latex
\documentclass{book}
\usepackage{dvidrv} \usepackage{hrefout}
\usepackage{xbookjh}
\usepackage{xstyle}
\usepackage{verbatim}
\begin{document}
etex

beginfig(1);
label("Au dessus  ",(0,0));
label(btex Au dessus  etex, (0,0));
endfig;
bye;


--- xbookjh.sty
\ProvidesPackage{bookjh}[2001/05/24 Material for _Linear Algebra_ (JH)]

\usepackage[\dvidrv]{color}
\usepackage[\dvidrv]{graphicx}  %
  \DeclareGraphicsRule{*}{mps}{*}{} % make pdflatex take fig.1 as metapost.
%  \DeclareGraphicsRule{*}{eps}{*}{} % make pdflatex take fig.1 as metapost.
\endinput

--- xstyle.sty
\AtBeginDocument{\newlength{\heightofcdot}
\newlength{\widthofcdot}
\settoheight{\heightofcdot}{$\cdot$}
\settowidth{\widthofcdot}{$\cdot$}
\newsavebox{\dotprodcircle}
\savebox{\dotprodcircle}{\includegraphics{dotprod.1}}
\newcommand{\dotprod}{\mathbin{\raisebox{.5\heightofcdot}{
          \makebox[\widthofcdot]{$\smash{\usebox{\dotprodcircle}}$}}}}}


Alternatively if I use stmt, \DeclareGraphicsRule{*}{mps}{*}{}
and comment out all the lines in xstyle.sty no error is generated
when mpost is run.

I don't understand what in xstyle.sty can be having an affect on
\DeclareGraphicsRule{*}{mps}{*}{}.

Can anyone provide any helpful information?

My preference is to use mps and not eps.