xhtml1 transitional dtd 500 error

I am receiving a 500 error on the following dtd file.  Is this  
supposed to be removed.

http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd
-- 
Justin England
justengland@gmail.com

Received on Sunday, 3 January 2010 17:53:47 UTC