Ran into a problem when installing Oracle Identity Management into a WLS 11g. Registering the OID with opmnctl gave me an oracle.as.config.ProvisionException.
Solved it by extending the domain (although the configuration of the OID was specifically set to No Domain). Make sure that the Enterprise Manager is in the domain.
After that (and this is the important part) make sure to restart the domain, at least the AdminServer.