<!--Sample XML -->
<?xml version="1.0"?>
<?xml-stylesheet type="text/css" href="style.css"?>
<BOOKS>
<BOOK>
<TITLE CLASS="BLUE">WELCOME</TITLE>
<AUTHOR>SAMPLE</AUTHOR>
</BOOK>
</BOOKS>
You have wrongly closed the comment on the first line. Check the above first line for correction.