Unable to Delete Computer Group (in WUS 3.0 Beta 2)

When I try and delete an old Computer Group that I no longer want to use in
WUS v 3.0 Beta 2 I get an hour glass icon appear against the icon that
represnts that Computer Group, I also (sometimes) get a "Deleting" progress
bar that implys that it's trying to do something ......


After a minute or more the WUS 3.0 Console crashes with the following error:
End Snap-In window stating that the snap-in in not responding.


The central WUS3.0 console window reports that:
"An Unexpected Error Occured"
"FX:{8b6499ed-0241-e032-6508-da4b1c879d7e}"
An error occurred.

System.InvalidOperationException -- Response is not well-formed XML.

Source
System.Web.Services

Stack Trace:
at System.Web.Services.Protocols.SoapHttpClientProtoc ol.Invoke(String
methodName, Object[] parameters)
at
Microsoft.UpdateServices.Internal.ApiRemoting.Exec uteSPDeleteTargetGroup(Guid
id, String adminName, Boolean failIfReplica)
at
Microsoft.UpdateServices.Internal.DatabaseAccess.A dminDataAccessProxy.ExecuteSPDeleteTargetGroup(Gui d id, String adminName, Boolean failIfReplica)
at Microsoft.UpdateServices.Internal.BaseApi.Computer TargetGroup.Delete()
at
Microsoft.UpdateServices.UI.AdminApiAccess.WsusCom puterTargetGroup.Delete()
at
Microsoft.UpdateServices.UI.AdminApiAccess.WsusCom puterTargetGroup.Delete(RemoveComputerGroupAction action)
at
Microsoft.UpdateServices.UI.SnapIn.Scope.Computers ListScopeNode.RemoveComputerTargetGroup()



Any help would be much appreciated.

Thanks very much,
Robin.