DOCBOOK: Possible bug in DOCBOOKX dtd

Hi,
I was trying to open the DOCBOOKX.dtd in IE 5.5 and received the following
error:

                                            
 The XML page cannot be displayed           
                                            
                                            
 Cannot view XML input using style sheet.   
 Please correct the error and then click    
 the Refresh button, or try again later.    
                                            
                                            
 Cannot have a DTD declaration outside of a 
 DTD. Line 61, Position 12                  
                                            
                                            
 <!ENTITY % sgml.features "IGNORE">         
 -----------^                               
                                            



Is this a bug with the DTD or ...?

Just wanted to let you know.

Omar