You do not have permission to create chat rooms in Microsoft Office Communications Server 2007 R2, Group Chat. However, the Create a Chat Room command in the Connect menu is available in your Group Chat client.
To resolve this issue, install the following cumulative update:
2491979 Description of the update for Office Communications Server 2007 R2 Group Chat client: March, 2011
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.
After you apply this update package, the Create a Chat Room control on the Connect menu becomes unavailable.