error while compiling

Hello, I am working on a french translation for the documentation.

I read the tutorial about compiling, so I checkout the latest cvs and 
try to compile the english version first, but I got an error while 
compiling :

# scripts/gen_manual.sh en html
Writing ../build/en/html/copyright.html for legalnotice
Writing ../build/en/html/preface.html for book
Writing ../build/en/html/tutorials.installation.windows.html for sect1
Writing ../build/en/html/tutorials.installation.linux.html for sect1
Writing ../build/en/html/tutorials.installation.macosx.html for sect1
Writing ../build/en/html/tutorials.installation.macosx-stepbystep.html 
for sect1
Writing ../build/en/html/tutorials.installation.html for chapter
runtime error: file ../stylesheets/html/name_to_id.xsl line 52 element 
choose
Variable 'class' has not been declared.
Highlighting files.........
highlighting complete
copying image files

0 image files copied

I am using php5 :
# php --version
PHP 5.2.0-8+etch3 (cli) (built: Apr 29 2007 10:42:07)
Copyright (c) 1997-2006 The PHP Group
Zend Engine v2.2.0, Copyright (c) 1998-2006 Zend Technologies

Does anybody can help me ?

Thanks in advance,
Benjamin.