DSXchange

I am using TX8.0 to import XSD to create typetree. The import wizzard gives 2 options for validation 1) Xerces 2) Classic.
When I used Xerces option, it successfully created the tree.
but when I used Classic option, it gave following error :-
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A JAVA EXCEPTION HAS BEEN ENCOUNTERED DURING THE DOCUMENT PARSING
JAVA EXCEPTION: null
CODE STACK:
java.lang.NullPointerException at com.ascentialsoftware.xmlsimp75.MetadataValidator.allowForNamespacePrefixesForQualifiedAttributes(Unknown Source) at com.ascentialsoftware.xmlsimp75.MetadataValidator.validate(Unknown Source) at com.ascentialsoftware.xmlsimp75.XmlSchemaImporter.importXmlSchema(Unknown Source) at com.ascentialsoftware.xmlsimp75.XmlSchemaImporter.generate75MtsFile(Unknown Source)
PARSE STACK:
EMPTY OR NOT AVAILABLE
==========================================
What could be the problem ? Do I need JDK installed on my machine ?
Please advise.