This seems to be same problem than in ticket -> https://jira.pentaho.com/browse/BISERVER-14811
1: Please find the pdm-ce-3.8.0.1.jar
in the following location:
"tomcat/webapps/pentaho/WEB-INF/lib
2: Please move this file to another location (outside of the Pentaho directory).
3: Please restart your Pentaho Server and Test.