What AS and version are you deploying on?
You should be able to run the editor in standalone mode with:
http://localhost:8080/designer/editor/?profile=default&uuid=xyz (replace xyz with an unique id for your process instance).
When working in standalone mode (outside of Guvnor) note that your processes will be saved onto the file system ($jbossHome/server/$config/deploy/designer.war/WEB-INF/repository/) in json format only.