[XeTeX] Error using Memoir Class

[Alan Jones]

Hi:

I found a basic script for Memor class.

%!TEX TS-program = xelatex
%!TEX encoding = UTF-8 Unicode

The following basic preamble will do the job to begin with. I use the
memoir class. This class is very convenient for long documents.

%!TEX TS-program = xelatex
%!TEX encoding = UTF-8 Unicode
\documentclass[10pt]{memoir}
\usepackage{xltxtra,fontspec,xunicode}
\defaultfontfeatures{Scale=MatchLowercase}
\setromanfont[Numbers=Uppercase]{Hoefler Text}
\setmonofont[Scale=0.90,Ligatures=NoCommon]{Courier}

\title{Your Title}
\author{Your Name}
\date{}

\begin{document}

\maketitle
\chapter{Title}

\section{Section Title}
Your text

\subsection{Subsection Title}
Your Text
\end{document}


I get these error when I compile it.

This is XeTeXk, Version 3.141592-2.2-0.996-patch2 (Web2C 7.5.6)
 %&-line parsing enabled.
entering extended mode
(./book.tex
LaTeX2e <2005/12/01>
Babel <v3.8h> and hyphenation patterns for english, usenglishmax, dumylang, noh
yphenation, loaded.
(./memoir.cls
Document Class: memoir 2009/09/21 v1.61803398b configurable book, report, artic
le document class
(/usr/share/texmf-texlive/tex/generic/oberdiek/ifpdf.sty)
(/usr/share/texmf-texlive/tex/generic/ifxetex/ifxetex.sty) (./ifluatex.sty)
(/usr/share/texmf-texlive/tex/latex/etex/etex.sty) (./mem10.clo)
(/usr/share/texmf-texlive/tex/latex/memoir/mempatch.sty

! LaTeX Error: Command \m at mscap@capbox already defined.
               Or name \end... illegal, see p.192 of the manual.

See the LaTeX manual or LaTeX Companion for explanation.
Type  H <return>  for immediate help.
 ...

l.67 \newsavebox{\m at mscap@capbox}

.

Thanks for your help,

Regards,
Alan