Log in as administrator.
Stop and delete the Release 5 Service Registry (Application Server) domain.
cd ServiceRegistryR5-base\install
ant -f build-install.xml appserver.domain.stop appserver.domain.delete
Run the Release 5 uninstaller to uninstall Release 5 Service Registry.
Start the Release 4 Service Registry (Application Server) domain.
cd ServiceRegistryR4-base\install
ant -f build-install.xml appserver.domain.start