Kiln is a multi-platform framework for building and deploying complex websites whose source content is primarily in XML. It brings together various independent software components into an integrated whole that provides the infrastructure and base functionality for such sites.
Schematron validation currently results in NullPointerExceptions.
As it looks, the Schematron XSLTs require XSLT 1.0 compatibility mode, which is not implemented in Saxon HE.
If the XSLTs are upgraded to XSLT 2.0 only (cf. Schematron/schematron#55) it should be straightforward to replace the files and get this working again.