New user: trying to use XSLT Service

I’m new to WebMethods and trying to covert XML to string with pipe in between the data. I followed User Documentation when made me end up here. Anyone please help me in solving this problem.

com.wm.app.b2b.server.ServiceException: com.wm.pkg.xslt.util.LocalizedTransformerException: [XSL.0002.9002] JAXP: Error during transformation - Content is not allowed in prolog.; SystemID: file:///C:/; Line#: 1; Column#: 1

I wasnt providing the DTD in XMLURL.

I am getting LocalizedTransformerException ([XSL.0002.9002] JAXP: Error during transformation - Unknown error in XPath.; SystemID: file:///C:/…/…/…/.testfile.xsl; Line#: 3545; Column#: 92) while converting an xml file to html. Please advice how to go about the issue. Is it an xml file related issue, the xslt file, or is this a wM bug.