I am trying to install Forms 12.2.1.3.0 on Windows 8 using Java 12.0.2 and I get the following exception

CFGFWK-64254: Error occurred in "OPSS Processing" phase execution
Se ha encontrado un error: oracle.security.opss.tools.lifecycle.LifecycleException: Error al configurar el almacén de seguridad de la base de datos. Excepción oracle.security.opss.tools.lifecycle.LifecycleException: oracle.security.jps.service.policystore.PolicyStoreException: Exception [EclipseLink-30005] (Eclipse Persistence Services - 2.6.5.v20170607-b3d05bd): org.eclipse.persistence.exceptions.PersistenceUnitLoadingException
Exception Description: An exception was thrown while searching for persistence archives with ClassLoader: java.net.URLClassLoader@79b6d394
Internal Exception: java.lang.NullPointerException.
I am using an Oracle 12c database to hold the schemas Fusion requires
I've already read the following discussion that has a similar problem but I'm only creating one domain and for one repository:
I've tried creating another set of database accounts using RCU and didn't worked.
Does anybody know how to get round this problem?