First, the authentication in DM 4.0 has changed and RPE needs to be patched. There are patches for RPE 1.1.2 and the recommend RPE 1.1.2.2 on the DM wiki page for the DM-RPE tutorial (https://jazz.net/wiki/bin/view/Main/DMReportTutorial).

As for the URLs, in DM 4 a project can contain multiple workspaces (configurations) and each workspace have have a different set and version of associated ontologies. Therefore, ontologies can only be found if a configuration is specified in the URL. The configuration is a project/workspace combination specified by adding the URL parameters:

?project=<projectName>&workspace=<wsName>.

If you only specify the project=<projectName> parameter, the default workspace is used. Also, in DM 3.0, all ontolgies were automatically associated with every project but in DM 4.0, each project can associate a subset of the ontologies (the project properties page ... Domains tab) by associating a domain with the project (the ontologies defined by the domain are then available). For example, if you do not associated the RSA BPMN domain with a project (say project Abc), then the reporting URL https://<host:port>/dm/reporting/bpmn?project=Abc will not be available.