WAAD Connector for FIM Problem

I have a new FIM 2010 R2 box running v4.1.3496.0.

I have installed .Net4, sign-in assistant for WAAD and the latest version of the connector v1.0.6635.0069 from last month.

I managed to create a new MA in FIM no problem but when I tried out the first Full Import I am getting an odd error

Failure while importing entries from Windows Azure Active Directory. Exception: System.Collections.Generic.KeyNotFoundException: The given key was not present in the dictionary.
   at System.Collections.Generic.Dictionary`2.get_Item(TKey key)
   at System.Collections.ObjectModel.KeyedCollection`2.get_Item(TKey key)
   at Microsoft.Azure.ActiveDirectory.Connector.Connector.GetConnectorSpaceEntryChange(SyncObject syncObject)
   at System.Linq.Enumerable.WhereSelectListIterator`2.MoveNext()
   at System.Collections.Generic.List`1.InsertRange(Int32 index, IEnumerable`1 collection)
   at Microsoft.Azure.ActiveDirectory.Connector.Connector.GetImportEntriesCore()
   at Microsoft.Azure.ActiveDirectory.Connector.Connector.GetImportEntries(GetImportEntriesRunStep getImportEntriesRunStep).

Can anyone tell me why I might be getting this error?

Thanks

andy