vCAC6.1 Cannot see users and groups in entitlements

Hi

Im running a POC of vCAC 6.1 and i seem to have got stuck on a bit.  When i try and add an entitlement to a Business group, there is nothing to search on or select from the "users and groups" section.  My suspicion is that this is related to the "Active directory container" section in the Business Group which is simply a free text field with no indication of what needs to go in there.  Although i may be mistaken.

Any help would be greatly appreciated.

Thanks in advance

Richard