It's saying that your XML is invalid - probably the XML of the stylesheet rather than the source document. We don't need a Java stack trace to help you with this, we need to see your XML source. The error message probably means exactly what it says. Trying to parse the XML in an environment such as Stylus Studio or XML Spy may point you more directly to the place where the error occurs.
Author, XSLT Programmer's Reference and XPath 2.0 Programmer's Reference