basic problems converting the test files

I´m starting with docbook and I´m having several problems trying to
put it running...

I downloaded all docbook files (CVS from the open repository)
I installed the xsltproc and it is running well

then I changed to the directory TESTS and tryied to run the following
command line:

xsltproc  --output html/book.html  --stringparam use.extensions 0 
C:\cvsRepository\docbook\xsl\html\docbook.xsl  book.001.xml

I got the following error:

tests/test.xml:2: warning: failed to load external entity "website.dtd"
<!DOCTYPE webpage SYSTEM "../website.dtd">

It seems some configuration I messed...

any tip will be greateful,

   Felipe Gaúcho