DTD is missing in PIP builder


I’m using wM 9.6 trial version and try to import one PIP using PIP Builder. I have put DTD and zip in /opt/softwareag/IntegrationServer/packages/WmPIPTools/import. However, PIP Builder still doesn’t recognize this dtd and give this warning: “Warning: A DTD MUST be in the PIP Tools import directory before building a Pip” and DTD list is not populated with any value.

Please help.