vCO 5.5.1 - user unknown

So I installed the GA of Orchestrator 5.5.1 yesterdy and can't seem to authenticate.

I've tried both LDAP and SSO configurations, following the documentation to the letter,  and get the same error each time:

2014-03-13 10:10:31.063+0000 [http-bio-0.0.0.0-8281-exec-9] ERROR {} [VcoFactoryServiceFacadeProxy] javax.security.auth.login.LoginException: Cannot login user : myuseraccount, user unknown

I'm running vCenter/SSO etc 5.5.0b and have deployed the vCO 5.5.1 appliance.

Anyone having this issue too? Or am I going mad?

Cheers