[Rd] \middle in Rd.sty conflicts with newer LaTeX?

[Na Li]

Rd.sty defines 

\newlength{\middle}

which seems to be in conflict with the my latex installation.

Here is a minimal example:

\documentclass{article}
\newlength{\middle}
\begin{document}
\end{document}

It runs fine on a Linux box:

carp:136% latex test.tex 
This is TeX, Version 3.14159 (Web2C 7.3.1)
(test.tex
LaTeX2e <2000/06/01>
Babel <v3.7h> and hyphenation patterns for american, french, german, ngerman, i
talian, nohyphenation, loaded.
(/usr/share/texmf/tex/latex/base/article.cls
Document Class: article 2000/05/19 v1.4b Standard LaTeX document class
(/usr/share/texmf/tex/latex/base/size10.clo))
No file test.aux.
(test.aux) )
No pages of output.
Transcript written on test.log.

but fails on a Mac with the TeX installed using GW's i-installer:

bass$ latex test.tex 
This is e-TeXk, Version 3.141592-2.1 (Web2C 7.5.2)
 \write18 enabled.
 %&-line parsing enabled.
 (/usr/local/teTeX/share/texmf.tetex/web2c/cp8bit.tcx)
entering extended mode
(./test.tex
LaTeX2e <2001/06/01>
Babel <v3.7h> and hyphenation patterns for american, nohyphenation, loaded.
(/usr/local/teTeX/share/texmf.tetex/tex/latex/base/article.cls
Document Class: article 2001/04/21 v1.4e Standard LaTeX document class
(/usr/local/teTeX/share/texmf.tetex/tex/latex/base/size10.clo))

! LaTeX Error: Command \middle already defined.
               Or name \end... illegal, see p.192 of the manual.

I couldn't find where \middle is defined.  Has anyone else experienced
the same problem?  

Michael

-- 
Na (Michael) Li, Ph.D.               
Division of Biostatistics          A443 Mayo Building, MMC 303   
School of Public Health            420 Delaware St SE            
University of Minnesota            Minneapolis, MN 55455         
Phone: (612) 626-4765              Email: nali at umn.edu                  
Fax:   (612) 626-0660              http://www.biostat.umn.edu/~nali