I think you may be facing this issue because you are using the JPA Identity Store without define the entities mapping the identity model types in your META-INF/persistence.xml.

Can you check that ? You need something like that if you're using the Basic Identity Model provided by PicketLink.

https://github.com/jboss-developer/jboss-picketlink-quickstarts/blob/master/picketlink-authorization-idm-jpa/src/main/resources/META-INF/persistence.xml

As you may notice, you need to specify the entities mapping your types. In this case, all those entities are provided by picketlink-idm-simple-schema dependency. Which is just a default/sample mapping for the Basic Identity Model.

Regards.