Bug#215925: package "index" dislikes "\backmatter"

[Thomas Pichler <taupi@aon.at>]

Package: tetex-extra
Version: 2.0.2-4.2
Severity: normal

>---begin example---
\documentclass{book}
\usepackage{index}
\begin{document}
\chapter{$\mathbf{x}$}
\backmatter
\end{document}
---end example---<

LaTeXing the above example leads to the error message

>---error msg---
! LATEX ERROR: \MATHBF ALLOWED ONLY IN MATH MODE.

SEE THE LATEX MANUAL OR LATEX COMPANION FOR EXPLANATION.
Type  H <return>  for immediate help.
 ...                                              
                                                  
l.6 \backmatter
----error msg---<

- Removing "\backmatter" OR 
- substituting "$x$" for "$\mathbf{x}$ OR
- substituting "\section" for "\chapter" OR
- adding a "\section" command after the "\chapter" command OR
- using the documentclass "amsbook" instead of "book"
makes the error disappear.

best regards, tom.

-- System Information:
Debian Release: testing/unstable
Architecture: i386
Kernel: Linux odin 2.4.21-4 #1 Fri Aug 8 21:42:54 CEST 2003 i686
Locale: LANG=C, LC_CTYPE=C

Versions of packages tetex-extra depends on:
ii  dpkg                       1.10.15       Package maintenance system 
for Deb
ii  gsfonts                    6.0-2.1       Fonts for the ghostscript 
interpre
hi  perl-tk                    1:800.024-1.1 Perl module providing the 
Tk graph
ii  tetex-base                 2.0.2-4.2     Basic library files of 
teTeX
ii  tetex-bin                  2.0.2-4.3     The teTeX binary files

-- no debconf information